History GoddamnedBats / ArkhamHorrorTheCardGame

* The "Crypt Chill" treachery from the "Chilling Cold" set forces the investigator to pass hard Willpower check or discard one asset from play (or losing health if it's impossible). The check is hard enough that some investigators wouldn't be able to reliably pass it.

* "The Yellow Sign" treachery from the "Agents of Hastur" set has hard enough Willpower check 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 check, 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 check 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.

* "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 check, but it must be done ''after'' gaining it, and yes, failing that check ''also'' triggers the "Haunted" effects.

* "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 check it (and thus, discard excessive cards) every time you draw anything.

* "Malfunction" treachery from namesake set can randomly break your Vehicle, forcing you to stop and pass a not-trivial Intellect check 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.

*** "Memory Variant" forces you to set aside as "hollow" any event card you play. It may be discarded by passing a Willpower check of above-average difficulty.

** "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 check; good luck doing it as Rogue.

** "Heavy Rain" treachery puts investigator through Willpower check, 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.

* "Dead Heat" scenario has "Cornered!" treachery, which forces you to pass Willpower check; 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.

** "Shadowed" and "Accosted" treacheries, on top of extra Doom, forces investigator to pass a Willpower/Agility checks to avoid suffering horror/damage, respectively.

* Coterie Agent enemy form "Crimson Conspiracy" set makes 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 from "Crimson Conspiracy" set 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.
* 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, while "hollowed" card would be missed for a while even after the enemy gets defeated.
* "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, while "Key Charge" makes each Coterie member shift their Keys, which comes with various nasty effects, after while it "surges" into other card.
* "Secret War" set is another bunch of "hollow"-centred chaos, ravaging the player's decks without directly killing them.
** "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 check of above-average difficulty.
* "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.
* "Spreading Corruption" set:

** "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, but they're not fatal on their own. For extra annoyance, it has "Peril" keyword, so no outside help.

* 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 vey strong on its own, but frequently shows with the other cards which can add more Doom to it.

* Swarm enemies in general; 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.

* "Prismatic Phenomenon" treachery from the "Dreamlands" set works similarly to the "Frozen in Fear", but targets drawing cards, gaining resources or playing cards. 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 they 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).
* 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 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.
* "Song of the Magah Bird" and "Wondrous Land" (from "The Search for Kadath" scenario) both aims to slow down the investigation, 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.

* Cats from Saturn enemy from "Dark Side of the Moon" scenario whose "swarm" value goes higher as the alert level goes higher, which can make them very slow to dispatch. But they lose "swarm" cards one by one whenever they move or gets evaded.
* "Restless Journey" 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 [[BossInMookClothing 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 nasties encounter cards which targets players' hand, as it hits ''all'' investigators, and forces to discard all assets and events with specific cost. On the bright side, it only triggers when failing a Willpower test, and scales up with how bad you deal with it. It has "peril", preventing you friends from assisting.

* 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 Initiate receives massive boost to Fight and Evade while has no Doom, and Priest outright can't be defeated, ensuring that they ''would'' live until they generate those.

* "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 has them both.

* "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.

* "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.y easily can force you to discard everything in your hand and play area, wrecking your entire plan of action.

* "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. It ver

* "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.
* "Realm of Madness" treachery from "The Pallid Mask" is another card which forces to discard cards, but it scales with horror suffered, which, in this scenario, can exceed your usual maximum. It very easily can force you to discard everything in your hand and play area, wrecking your entire plan of action.

* "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 you tons of headache to you personally later in campaign, and possibly even cause you traumas.

* "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 deal to investigator instead. And if you have nothing, it targets your hand instead, discarding 3 cards. No matter what, it ''would'' screw you over.

* "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.

*** "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.

* 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 "hunter".

* 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 it can't reach the investigators in one move, it's borderline impossible to outrun him -- wile 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.

* 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.

* 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.
* 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.

* 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 jus 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.

[[folder: Repeat offenders]]