Goddamned Bats / Arkham Horror: The Card Game

Many treacheries and some enemies can't outright kill investigators, but instead aims to halt their progress (in a game with strict time limit), by either directly stalling them, making them waste limited actions or harassing their valuable cards. Besides recurring cards from the core game's campaign, each expansion introduces new ways to torture the players.

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Core game

• The "Rotten Remains" treachery from the "Striking Fear" set. It tests Willpower, and deals horror if investigator fails, proportionally to how hard they fail it; Rogues suffers the most, generally having poor Willpower and limited number of options to boost it. Having three copies in the deck, and coming from one of the most recurring set in the game, it would come to cause you problems time and time again. It also has a twin brother, "Grasping Hands" from the "Ghouls" set, which tests Agility and deals damage, but it's way less common and thus less infamous.
• The "Frozen in Fear" treachery from the "Striking Fear" set forces investigator to waste (limited) actions on even the most basic tasks, which, in turn, would slow down their progress so much, they likely wouldn't make it in time; the only way to discard it is to pass Willpower test, which may be problematic when playing as Rogue. Whenever it comes to deciding what to cancel, this card is amongst the top priority ones, alongside "Ancient Evils".
• The "Crypt Chill" treachery from the "Chilling Cold" set forces the investigator to pass hard Willpower test or discard one asset from play (or losing health if it's impossible). The test is hard enough that some investigators wouldn't be able to reliably pass it.
• Acolyte from "Dark Cult" set; not only it spawns with 1 Doom on it, but it spawns in an empty location, meaning that you have to go out of your way to get that time back. There are enough of them in the deck to show up time and time again, and it's one of the sets which would show up in nearly every campaign at least once. It isn't very strong on its own, but frequently shows with the other cards which can add more Doom to it.
• Hunting Nightgaunt enemy has only one notable ability — it doubles negative modifiers on every chaos token you draw when trying to evade it, which often makes doing so borderline impossible (especially since it has the "Hunter" keyword, which makes it actively pursuing investigators).
• "The Yellow Sign" treachery from the "Agents of Hastur" set has hard enough Willpower test that investigators can reliably fail to pass it and suffer horror, but the more annoying effect is that it can force investigator to draw a weakness with "Madness" trait from their deck; if the player doesn't have such cards, it's a freebie, but if they do, it can screw them over, as the list of such cards includes some very nasty ones (and for some investigators, it's a part of their signatures).
• The "Dreams of R'lyeh" treachery from the "Agents of Cthulhu" set reduces investigator's Willpower and Sanity, until they deal with this card. The problem is, to discard that card, you have to pass Willpower test, while suffering from the stats reduction effect. And penalty to Sanity is very painful for any investigator who has low stat to begin with.
• The Locked Door treachery spawns on whichever location has the most clues and prevents it from being investigated until an investigator passes a moderately difficult skill test of 4 fight (to break the door) or 4 agility (to pick the lock). Your clue gatherers will likely struggle to pass this test without assistance, and if this happens on a location critical to the scenario (e.g. the only one with clues left) this can seriously slow the team down and potentially cost them the scenario.

The Dunwich Legacy campaign

• The Conglomeration of Spheres enemy from the "Hideous Abominations" set lacks offensive capabilities, but has more health than some investigators, and forces investigator to discard any Melee cards used against it — and non-Melee cards usually have limited ammo or charges.
• "Claws of Steam" treachery from "The Essex Express" scenario forces to pass a Willpower test; on a failure, it not only does damage (tolerable), but also makes investigator unable to move for entire round... in scenario with Advancing Wall of Doom. There's also the "Broken Rails" treachery, which makes investigators lose 1 action, but it's less deadly.
• "Collapsing Reality" treachery in the "Lost in Time and Space" scenario not only causes damage (and horror, due to scenario-specific rules), but discards your location and drops you in the very beginning. Have fun spending several more turns going back to where you were before this card hit you.

The Path to Carcosa campaign

• Roach Swarm enemy from "Decay and Filth" set exists to annoy clue-searchers; they're just hard enough to evade to require some card investment, and have their combat scaling with locations shroud, making it hard to swap them. If investigator tries to investigate with them still being nearby, they would be just hit by attacks of opportunity. Fortunately, they deal only 1 point of damage.
• "Corrosion" treachery from "Decay and Filth" set exists to harass any investigators who relies on key assets, as it makes them discard multiple assets at once, with severity scaling with shroud. Its counterpart from Return to the Path to Carcosa instead targets events, which is just as annoying.
• "Delusions" set rarely poses real threat, but it's very annoying, due to putting various restrictions on the player and only being discardable by wasting almost all your actions. The one card which doesn't do that, "Descent into Madness", instead makes investigator losing actions if they have enough horror, which they usually have, given this campaign's focus.
• "Straitjacket" treachery from "The Unspeakable Oath" scenario, once drawn, forces investigator to wear it (taking both hands and a body slots), and can't be removed except by spending two actions. It may outright put investigator out of action for some time.
• "A Shadow Behind You" treachery from "The Pallid Mask" forces investigator to waste one action every turn (remember that you're on a time limit), or discard either all resources or all cards from had to get rid of it (can be very painful for most investigators).
• "Realm of Madness" treachery from "Dim Carcosa" is another card which forces to discard cards, but it scales with horror suffered, which, in this scenario, can exceed your usual maximum, potentially making it extremely devastating.

The Forgotten Age campaign

• "Entombed" treachery from "Deadly Traps" set exists solely to make investigator stuck in one place and waste actions to get rid of it. And test difficulty is just hard enough to potentially require more than one attempt.
• "Lost in the Wild" is similar to "Entombed"; unlike it, it can be avoided, but also unlike it, if it actually lands, that's it: you're stuck until the end of your turn.
• "Pit Viper" enemy from "Serpents" set is very easy to kill, but doing so costs vengeance points, which would hurt investigators in the long run. If you decide to deal with it non-lethally, any mistake can result in you ending up poisoned, which can cause tons of headache to you personally later in campaign, and possibly even cause you traumas.
• Boa Constrictor enemy from the "Serpents" set is hard to kill (though its damage output is low), can prevent you from readying your assets (making it much harder to deal with it if you failed to dispatch it quickly), and if you still kill it, you get the whopping two vengeance points. You can try to avoid it, but it wouldn't avoid you, being a "hunter" enemy.
• "Snake Bite" treachery from the "Serpents" set forces to choose between essentially One-Hit Kill for any Ally, or direct damage to investigator themselves and being poisoned (which would cause massive headache to the player later in campaign).
• "Lost in Time" treachery from the "Temporal Flux" set forces investigator to pick and shuffle non-story asset under their control back to the deck, without any saving throws; if that asset had any damage or horror on it, those gets dealt to investigator instead. And if you have nothing, it targets your hand instead, discarding 3 cards. No matter what, it would screw you over.
• Fang of Yig enemy (from "Yig's Venom" set) prevents poisoned investigators from playing cards or committing them to skill tests, essentially crippling them without actually doing anything to kill them. They don't pose much danger to non-poisoned investigators, however.
• "Timeline Destabilization" treachery from "The Boundaries Beyond" scenario aims to disrupt your progress. If drawn, it enforces the Willpower test (which scales with the number of discovered locations), and if the player fails to pass it, it goes into exploration deck, so, instead of a new location you want to find, you can accidentally draw this one, wasting that exploration. It also deals minor damage and horror.
• "Poisonous Spores" treachery from "The Heart of Elders" scenario poisons everyone who doesn't move away from its location before the end of the round. Those already poisoned instead suffers horror. Either run around instead of doing your task, or get poisoned and suffer even more later on; make your choice.
• Apex Strangleweed enemy from "The Heart of Elders" scenario has more health than some investigators, and though it lacks offensive capabilities, each time it makes attacks of opportunity, it takes away all investigator's actions and forces them the end their turn immediately. It can be disabled by one of the possible supplies (a pocketknife), but players are so limited in picking those, it's very likely that no one would bother to take it.
• "Ants!" treachery from "The Heart of Elders" scenario imposes hard Agility test, and forces investigators to discard cards from either play or hand; to make it worse, effect is scaling with how badly you perform the test. And there are multiple copies of this card in the deck.
• "Wracked in Time" treachery from "Shattered Aeons" scenario is yet another "fail a test, suffer damage" card... except for the fact that any asset which gets damaged by it, unless it's defeated, must be then shuffled back into your deck, making it harder to stay well-equipped while also avoiding losing too much health.

The Circle Undone campaign

• "Centuries of Secrets" treachery from the "City of Sins" set, if investigator is particularly unlucky, can severely hurt investigators who relies on key Allies, by dealing direct horror to each of them. It also deals direct horror to investigator themselves.
• "Realm of Torment" treachery from the "Realm of Death" set makes investigator trigger every "Haunted" effect in their location at the start of their turn, with all the chaos that follows. It can be discarded by passing Willpower test, but it must be done after gaining it, and yes, failing that test also triggers the "Haunted" effects.
• "Witchcraft" set consists of treacheries dedicated to make life harder, without actually ending it, be it through targeting your assets ("Bedeviled"), your hand ("Diabolic Voices") or your stats ("Wracked").
• Vengeful Witch enemy from "The Wages of Sin" scenario is tough enough to often warrant using extra cards to kill, but the worst part comes when she dies, as she deals direct damage and horror to all investigators around her, which you can't soak with your assets. And don't think you can just run from her, as she's a "hunter".

The Dream Eaters campaign

• Swarm enemies in general are nasty; with few exceptions, they're weak (with or without "swarm" cards), but the "swarm" cards they use are taken from investigators' decks, making killing them an urgency, as they can take something valuable this way. It also makes it harder to kill them, as each "swarm" card allows to absorb some damage while dealing more damage/horror. Some of them also combines it with extra effects which makes them even more annoying:
  • Zoogs. Small, somewhat cute, but they shows just how truly nasty the "swarm" mechanic can be:
    • Inconspicuous Zoog enemy from the "Zoogs" set combines "swarm" mechanic (with higher value than other zoogs) with inability to kill it in one attack, no matter what, as it cancels any excessive damage which would've otherwise targeted the other swarm cards or the host, and runs away to connected location. And even if it gets killed, it can respawn thanks to "Zoog Burrow" treachery.
    • "Zoog Burrow" treachery from the "Zoogs" set can add even more "swarm" cards to any zoog in play, or, if there's none, just outright spawn one from either the encounter deck or discard pile. You just barely killed the Inconspicuous Zoog after multiple turns? Too bad, it's here again.
    • Ancient Zoog from "Beyond the Gates of Sleep" scenario lacks its own "swarm" cards; instead, it just hides somewhere, and keeps adding more and more "swarm" cards to every other zoog, until you find and kill it. And it's also Elite, which makes it immune to many cards which would otherwise allow to quickly deal with it.
  • Cats from Saturn enemy from "Dark Side of the Moon" scenario; their "swarm" value goes higher as the alert level goes higher, which can make getting rid of them take much longer than the players can afford. But they lose "swarm" cards one by one whenever they move or gets evaded.
• "Will of the Spider Mother" treachery from the "Agents of Atlach-Nacha" set forces investigator to pass a Willpower test; the test becomes harder, due to inability to commit cards, if there're any Spider enemies in your location (and this card shows up in the situations where all your enemies are spiders), and if you fail it, you can't investigate or fight until the end of the round — while still having to deal with spiders in your location and being on a time limit.
• "Law of 'Ygiroth" treacheries from the "Agents of Nyarlathothep" set not only puts restrictions on what player can or can't do, but also makes it in such a way that just checking the conditions becomes annoying task (like "you can't play the cards with odd number of words in the title"). And they're "hidden", meaning that they would occupy your (limited) hand until you perform (equally awkward) condition to discard them.
• "Deeper Slumber" treachery from the "Dreamer's Curse" set targets everyone who likes to keep good cards at ready in their hand, by drastically reducing hand size and forcing to test it (and thus, discard excessive cards) every time you draw anything.
• "Prismatic Phenomenon" treachery from the "Dreamlands" set works similarly to the "Frozen in Fear", but targets drawing cards, gaining resources or playing cards; essentially, rather than take away your actions, it makes you unable to do anything useful with them half the time. It's also harder to discard, as you have to successfully investigate a location, which may be problematic for investigator who's not the best at it, especially while under effects of this card.
• "Night Terror" treachery from the "Merging Realities" set goes into your threat area, and hits you each time you fail any test (which can be very painful for Survivors, who actually have it as their core mechanic), by forcing to reveal 3 cards from your deck; each weaknesses immediately gets drawn, while any other cards gets outright removed from the game. You have to pass a Willpower test to remove it, which you also can fail (though, fortunately, the card gets removed regardless).
• "Song of the Magah Bird" and "Wondrous Land" (from "The Search for Kadath" scenario) both aims to slow down the investigation (in scenario with very strict time limit, and harsh long-terms consequences if you lose), on the threat of increasing Doom; first one locks you in location unless you pass a hard test, the second one can make you unable to investigate a location unless you're willing to get punished for it.
• "Endless Descent" from "A Thousand Shapes of Horror" scenario puts the top-most location on the bottom, essentially prolonging your descent — while you're against the timer and pursued by Advancing Boss of Doom.
• "Restless Journey" set of treacheries from the "Where the Gods Dwell" scenario tries to combine all the most annoying qualities in one cocktail. They makes you unable to commit more than one card to skill tests each round (seriously hurting your effectiveness), they're "hidden" (meaning that they take up limited place in your hand), and can only be discarded through skill test (each version tests different stat), failing each would also increase Doom. They also have "peril" keyword, so your friends wouldn't help you. And if all that wasn't enough, there's a Crawling Chaos lurking around which goes more and more dangerous the more "hidden" cards you accumulate, these ones included.
• "Abandoned by the Gods" treachery from the "Where the Gods Dwell" scenario is one of the nastiest encounter cards which targets players' hand, as it hits all investigators, and forces to discard all assets and events with specific cost. It only triggers when failing a Willpower test, and scales up with how bad you deal with it, but investigators with low Willpower (like most Rogues) can not only suffer themselves, but hurt entire team if gets caught unprepared. It has "peril", preventing you friends from assisting.
• "Caught in the Web" treachery from "Weaver of the Cosmos" scenario not only lowers your Agility, but also limits you to only one movement action per turn — in scenario where actively moving around is crucial for success, and where even main boss is actively trying to escape from you.

The Innsmouth Conspiracy campaign

• Initiate of Dagon and Priest of Dagon (both from the "Agents of Dagon" set) are another take at Doom-generating cultists, but with their own annoying gimmick. Both spawns without Doom by default, but while they don't have it, Initiate gains massive boost to Fight and Evade, and Priest outright can't be defeated; so even if they drop right on your head, you have to wait for at least a turn before dealing with them.
• Lloigor enemy from the "Agents of Hydra" set keeps pursuing investigators without actually engaging them (due to "aloof" keyword). While it's nearby, it forces all investigators in its or connected location to discard a random card from hand on every enemy phase. And if they decide to fight it after all, they would meet a very tough enemy with decent Fight whom they likely wouldn't kill fast enough to avoid being hit by its ability one more time.
• "Psychic Pull" treachery from the "Agents of Hydra" set not only forces investigator to discard a random card from hand, but then also imposes a Willpower test (with difficulty scaling with discarded card's cost) to avoid losing an action. Both effects are amongst most hated, and this card combines them.
• "Malfunction" treachery from namesake set can randomly break your Vehicle, forcing you to stop and pass a not-trivial Intellect test to fix it. It's not as painful in the "Devil Reef" scenario, which goes at more or less standard pace, but in the "Horror in High Gear", it may either slow you down while you're trying to outrun pursuit, or make you unable to slow down and investigate a road ahead to not run into something nasty.
• "Rising Tide" set exists to speed up the flood, and make it more painful for the players, on top of (often already nasty) scenario-specific effects. "Undertow" punishes the player for attempt to run away with damage and horror, unless they pass a skill test; "Riptide" is yet another asset discarder; and "Rising Tide" can make the flood go higher even faster than it usually does, and can become extremely annoying in "A Light in the Fog" scenario, where you have to fight off the flood in order to escape alive.
• Hunting Deep One enemy from the "Devil Reef" scenario can drug you from your boat, and then prevent you from jumping back unless you either kill it or evade it. Additionally, it prevents you from gaining resources, which may be painful when trying to dispatch it. And if you fail to quickly deal with it, you may run into this scenario's nasty pack of treacheries specifically made to grind investigators who think that they can survive without a boat.
• Hybrid Assassin enemy from the "Horror in High Gear" scenario can't hurt investigators much, but as he moves twice if her can't reach the investigators in one move, it's borderline impossible to outrun him — while fighting him wastes time and allows other, nastier enemies to catch up. He also spawns right on top of you, instead of far behind, like most other enemies in this scenario.
• "Eyes in the Trees" treachery from the "Horror in High Gear" scenario is yet another "pass a test or discard cards" treachery... which scales with your performance, and, if you're a driver, can hit your teammates.
• Deep One Hatchling enemy from "A Light in the Fog" scenario has abysmal stats, but if it's killed, it can and likely would attract attention of another, much stronger Deep One who would come for your blood. But if you stop trying to kill it, it wouldn't stop trying to kill you; and each time it tries to engage you, you have to choose between suffering small amount of horror, or losing an action. To make it even more annoying, it has "surge" effect, so once it spawns, it immediately gets followed by another card.
• Deep One Nursemaid enemy from "A Light in the Fog" scenario just quietly sits in a location, while passively boosting all the other, more dangerous enemies. But if you try to attack it, it would drop another encounter card on you (at least, it loses "surge" effect to not make it nastier than it has to be).
• "Taken Captive" treachery from "A Light in the Fog" scenario dumps investigator in the cell, from which they have to escape while also taking back their keys. This is in scenario which puts on strict time limit, and outright kills investigators if they fail to escape in time.
• "Stone Barrier" treachery from "The Lair of Dagon" scenario blocks the way out of its location, requiring passing a skill test every time you try to go through, which costs an action to even initiate.
• "Treacherous Depths" treachery from the "Into a Maelstrom" scenario forces the player to choose between increasing flood level, or discarding assets from play with their total cost scaling with you location's shroud; so, a choice between flooding location and getting even less place to breath, or potentially discarding tons of valuable cards, as shroud sometimes can be very high. As with all cards involving choices, it has peril, preventing your friends from bailing you out.

Edge of the Earth campaign

• Tekeli-li mechanic as a whole; a deck of various weakness cards which can get shuffled into your deck through a million-and-one ways, and screw you over when you lest expect it, while rarely, if ever, actually pose a danger directly. Enemies and treacheries who can drop such cards on the players are amongst the most annoying to deal with, though some are worse than others. Several sets exists primely to deliver those to the players:
  • Primordial Evil enemy from the "Agents of the Unknown" set is already very tough and hits hard, but it's not what makes it memorable; each time you damage it, you have to blindly shuffle Tekeli-li card into your deck, and because it's tough, it may take multiple turns to kill, thus costing you several such cards.
  • Manifestation of Madness enemy from "Creatures of the Ice" set shuffles two Tekeli-li cards on each attack. Due to it being a "hunter", it would never cease to pursuit you unless dealt with.
  • Glacial Phantasm slowly follows the investigators and then forces everyone in its location to shuffle Tekeli-li card, without giving a chance to avoid it.
  • "Blasphemous Vision" treachery from the "Nameless Horrors" set, on top of shuffling those cards into your deck, makes you resolve them twice each time you trigger them, until you get rid of it; but the true pain comes when it gets paired with the other cards from same set: "Glimpse the Unthinkable", just before shuffling card into deck, forces you to immediately trigger it, while "Nightmarish Vapors" gives a choice between wasting two actions (by itself extremely painful) or gaining two cards.
• Every single Elder Thing exists to torture investigators, in one way or another:
  • "Elder Things" set is all about harassing investigators' decks by forcing them to discard cards from it, be it when they attack you (Elder Thing Scavenger) or when you attack them (Guardian Elder Thing); both enemies have just enough health to possibly require more than one turn to deal with, and both are "hunters", meaning that you can't just run from them and forget.
  • Constricting Elder Thing enemy from "To the Forbidden Peaks" scenario gains more and more health the higher it spawns, and can prevent an investigator from advancing to the location above.
  • Benign Elder Thing enemy from the "City of the Elder Things" scenario, despite the name, isn't friendly and would attack investigators. It has 1-1-1 statline, making it easy to kill, but it spawns with Doom on it, and, if killed, adds that Doom directly to the current Agenda. What you're supposed to do with it is to pass a Willpower test to remove it from the game permanently, but you have to either spend two actions to engage and evade it, or just tank its attack of opportunity. Another issue with it is that there are enemies who can kill them for you (specifically, shoggoths), with the same results as if it was done by you.
• "Left Behind" set consists of two enemies who spawns with Doom on them. They're easy to kill... but it's actually the worst thing you can do, as it only makes their Doom tokens to move to their location instead. Instead, you're supposed to deal with them through specific non-lethal means, which would make them despawn... while they're trying to kill you. The set also includes a treachery which makes dealing with them even harder while adding more Doom.
• "Miasmic Torment" treachery from "Miasma" set attaches to your partner, and disables them, making them unable to get ready, and dealing either damage or horror to them once your turn ends. You can remove it, but it costs an action and requires a skill test. This thing can be quite annoying when you just can't afford to waste time.
• Giant Albino Penguin isn't aggressive, but makes you waste more turns each time you try to move from or into its location (it's "aloof", and thus wouldn't attack first). Grew tired of it and decided to kill it? But you would lose an action just to engage it, and then you have to kill an enemy with 3 health. In short, no matter what you do, the penguins would slow you down. And then there's "Wuk! Wuk! Wuk!" treachery, which can make the penguin move to your location, or put a Doom token on it (and if there's no penguins, it would just drop one on top of you).
• "Polar Mirage" treachery from the "Silence and Mystery" set flat-out discards all non-weakness cards from your hand if you try to discover clues in location to which it gets attached (and you have very little control over where it spawns). It can and would ruin your plan of action if drawn in the wrong moment. At least, it discards once it hits.
• "Hanging on the Edge" treachery from "To the Forbidden Peaks" scenario can deal you damage and drag you to location below, while any Expedition assets stays above and must be recovered. "Avalanche" treachery from same scenario is even worse, as it drags you immediately, and only then puts a skill test... to avoid being dragged even further. This card can easily undo several turns of progress.

The Scarlet Keys campaign

• Pretty much entire "Hollow" mechanic exists to annoy the players and slow them down (by temporarily removing their cards from the game), but some enemies exists solely to make it more annoying:
  • Paracausal Entity (from "Outsiders" set) is a "Hunter" enemy who forces an investigator who engages it to set aside a card they own as "hollow". It's relatively easy to kill, but would show up again and again (as there're multiple of them), while "hollowed" card would be missed for a while even after the enemy gets defeated.
  • Paradigm Effacer (from "Agents of the Outside" set) is both a "Hunter" (so it keeps pursuing investigators) and "Aloof" (so it doesn't attack on its own, and you have to engage it first, spending action). Just ending your turn in the same location is enough to lose a card as "hollow"; and it would persist and keep doing its dirty deed until killed or otherwise got rid of.
  • "Secret War" set exists to make players lose their cards as "hollows":
    • "Secrets Lost" forces the player to pass a non-trivial Willpower test, and punishes the failure with losing up to three cards as "hollows".
    • "Memory Variant" forces you to set aside as "hollow" any event card you play. It may be discarded by passing a Willpower test of above-average difficulty.
• Concealed mechanic. Concealed enemies goes "into shadows", leaving several mini-cards you have to uncover before you can kill them, with some of those being decoys. Most of such enemies are weak and easy to kill (once revealed), but often comes with the ways to make the search itself painful, and almost any enemy "in the shadows" has some way to harass the players without directly engaging them. In addition, some sets are made specifically to make already concealed enemies more annoying.
  • "Crimson Conspiracy" set is another take on annoying Doom-generating cultists; this time, you have to go out of your way to actually kill them:
    • Coterie Agent enemy is like Acolyte, but worse. Just like the Acolyte, Agent enters game with 1 Doom, but unlike them, they have newly-introduced Concealed keyword, so they would spread around the map and require looking for them to put down and get that time back. And that Doom can possibly stockpile in some scenarios.
    • "Conspiracy in Red" treachery puts more Doom on enemies in shadows (like Coterie Agents), or, failing that, just spawns the enemies with "Concealed" keyword. Concealed enemies are already pain in the back much of the time, but this card makes them worse.
  • "Figures in the Dark" treachery from "Dark Veiling" set either makes every enemy in shadows attack you (can be very painful if there're enough of them), or makes every investigator lose an action (wasting precious time). It usually can't cause your defeat by itself, but it certainly makes life harder for everyone. And "Peril" keyword makes it harder to counter.
  • Coterie Envoy from "Mysteries Abound" set prevents any concealed cards in its location from being exposed while it's alive; and as it's also "Aloof", you have to waste action to engage it before you can deal with it. Not very threatening on its own, it greatly amplifies the level of annoyance of the other enemies.
  • "Knives in the Dark" treachery (from "Shadow of a Doubt" set) deals 2 damage when you expose a decoy. Tolerable at first, it can quickly stockpile if there're many Concealed mini-cards, making you run out of damage soak options.
• "Scarlet Sorcery" set exists to make "Elite" Coterie members (read: mini-boss grade foes like the Beast or Amaranth) more dangerous and annoying, but can't kill the players on its own.
  • "Bound in Red" treachery increases all stats of the Coterie enemy with highest printed health (which is nearly always the already-dangerous main villain of scenario). Higher stats means more resources, cards and time wasted. And only way to remove it without a fight is by shifting a Key to unstable side, which is painful, and requires having a Key in the first place.
  • "Key Charge" makes each Coterie member shift their Keys, which comes with various nasty effects, after while it "surges" into other card. Specific danger varies depending on Key in question, as some effects are nastier than others.
• "Spreading Corruption" set exists to slow down the players, in the game where you're always on a time limit:
  • "Compulsion" treachery randomly triggers at beginning of your turn (you draw a chaos token to determine it), forcing you to waste two (out of three) actions to discard it (even if it would provoke attack of opportunity).
  • "Distorted Reasoning" treachery makes investigator unable to perform same action twice in a row (which can severely hinder any specialists, like dedicated clue-searchers). It can be discarded at the end of the turn, but it requires passing a Willpower test; good luck doing it as Rogue.
  • "Touch of the Beyond" treachery puts Doom on your asset with highest printed cost. It can be dealt with, and Mystics have the cards for removing Doom from assets (coincidentally, also introduced in The Scarlet Keys), but it's certainly unpleasant, as it takes away the precious time.
• "Strange Happenings":
  • "Heavy Rain" treachery puts investigator through Willpower test, and if they fail, either makes them take up to 3 horror (similarly to "Rotten Remains"), or drop up to 3 clues in their location; neither effect is nice, and low-Willpower investigators would suffer from it a lot.
  • "Pinch in Reality" treachery either discards half of your hand, or forces you to spend 1 Clue (not even discard; spending means it's gone); both effects would slow you down, albeit are still possible to recover from. For extra annoyance, it has "Peril" keyword, so no outside help.
• "Dead Heat" scenario has "Cornered!" treachery, which forces you to pass Willpower test; if you fail, either you suffer horror, or a civilian dies. Just as the card on which it's based, "Rotting Remains", it's gonna be hated by Rogues and other low-Willpower investigators.
• "Dealings in the Dark" scenario has several cards which puts more Doom on Cultists, in scenario where you're on a strict time limit.
  • "Shadowed" and "Accosted" treacheries, on top of extra Doom, forces investigator to pass a Willpower/Agility tests to avoid suffering horror/damage, respectively.
  • "Light Out of Void" treachery gives a choice between adding Doom on Cultist enemy with highest Evade, and suffering 1 damage and 1 horror; as with most cards involving Sadistic Choice, it has "Peril" keyword, so no outside help.
  • Umbral Harbinger enemy is relatively weak, but has 5 Health. What makes it nasty is the fact that anytime it gets damaged, a point of Doom gets put on Cultist. You can just keep avoiding it, as it has only 1 Evade, but as a "Hunter", it would keep pursuing you. Its danger can be reduced by just sending dedicated fighter who can finish it off quickly, and once dead, it stays dead.
• "Scarlet Shadows" scenario:
  • "Calling Card" treachery disables spending clues (stalling progress) until a location to which it gets attached gets successfully investigated with at least 2 successes.
  • Bound Nightgaunt enemy is a twin brother of Hunting Nightgaunt from the Core game (which is also present in this scenario). It mirrors the Hunting Nightgaunt, dealing horror instead of damage, and doubling negative modifiers on tokens drawn when attacking it; this can make investigators who're not well-prepared to fight it consider just running away from it, even if it has a non-trivial Evade rating.
• "Shades of Suffering" scenario has "Spirit Harvest" treachery, which forces investigator into Sadistic Choice between everyone suffering 1 damage and 1 horror (which can quickly stockpile, as there's more than one such card in the deck), and Tzu San Niang shifting her key (causing all investigators to lose an action, thus risking running out of time).

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