History ThatOneBoss / TerrariaCalamity

* Anahita and the Leviathan, albeit being more like an optional BonusBoss, are an extremely difficult DualBoss fight against the GlassCannon Anahita who is deceptively fast and hits very hard with both physical and ranged attacks that inflict StatusEffects (notably projectiles that spawn around you instead of being shot directly), and the MightyGlacier Leviathan (which joins the fight once Siren is at 40% health) who is slow but incredibly bulky, takes up most of the screen, and deals ridiculous damage with both rams and boulder shots that shred defense, all while summoning minions. While they're normally fought one at a time, both bosses will become active simultaneously once the Leviathan is brought below 40% HP as well. Managing both bosses and the constant swarm of minions can prove to be extremely difficult, especially since Anahita and the Leviathan cover each other's weaknesses extremely well. Oh, and [[KillOneOthersGetStronger whichever one is the last one alive will become enraged]]. No wonder they were voted the fifth hardest bosses in the entire game.

* Anahita and the Leviathan, albeit being more like an optional BonusBoss, are extremely difficult. It's a DualBoss fight against the GlassCannon Anahita who is deceptively fast and hits very hard with both physical and ranged attacks that inflict StatusEffects (notably projectiles that spawn around you instead of being shot directly), and the MightyGlacier Leviathan (which joins the fight once Siren is at 40% health) who is slow but incredibly bulky, takes up most of the screen, and deals ridiculous damage with both rams and boulder shots that shred defense, all while summoning minions. While they're normally fought one at a time, both bosses will become active simultaneously once the Leviathan is brought below 40% HP as well. Managing both bosses and the constant swarm of minions can prove to be extremely difficult, especially since Anahita and the Leviathan cover each other's weaknesses extremely well. Oh, and [[KillOneOthersGetStronger whichever one is the last one alive will become enraged]]. No wonder they were voted the fifth hardest bosses in the entire game.
* The Calamitas Clone. She's not too bad at first, although she can deal enormous damage and inflict the deadly Brimstone Flames debuff if you aren't careful. However, once you whittle her down enough, she'll summon a devastating HoldTheLine BulletHell that is guaranteed to take you down a few pegs if you aren't prepared, before adding in lightning-fast charges to her previous attacks. The real problem arises when she summons her brothers later on; Catastrophe and Cataclysm are extremely fast, do tons of damage, and use flamethrower/bouncing fire attacks that take up huge portions of the screen. Even if you figure out how to dispatch the brothers, you'll have ''another'' bullet-hell segment to deal with before Calamitas finally lets you kill her.

* Ravager quickly became this after receiving a massive rework. It has a colossal amount of health, deals stupidly high damage, and has a wide variety of attacks to hammer you with, including fireballs, homing flares, heat-seeking missiles, giant rock pillars, flaming lanterns that shoot fireballs at you, and of course its crushing physical attacks. All of these attacks will usually stack together to make patterns almost impossible to dodge. During its second phase, not only is it capable of terrifyingly fast, predictive jumps to slam down on players, it pulls out a few new tricks - not only is its head also chasing you around and vomiting even more projectiles than usual, you ''permanently have your flight time decreased by 50%''[[note]]And before you even think of it, it disables extra jumps and jump height boosts as well[[/note]], forcing you to stay (mostly) grounded and face the brunt of Ravager's attacks.

* The [[ClimaxBoss Devourer of Gods]] is downright ''infamous'' for being this. He's massive, has obscenely high health, moves incredibly fast, and deals insane damage with just about every attack on top of inflicting God Slayer Inferno, ''especially'' upon contact: enough that getting hit by its head in will more often than not result in instant death. Standard worm tactics with piercing weapons? Does next to nothing since anything that's not its head or tail takes next to no damage. Thought you could just build a platform in the sky to deal with it like you did with Destroyer? Well, too bad it doesn't need solid blocks to move. Try and outrun it? Not only does it fire long-ranged laser bursts which occasionally take on unconventional patterns, it will '''always''' be faster than you. Mobility? Neutered since just being near it warps gravity and flight. Still not enough for you? Well, when you beat him down a bit, he TurnsRed and enters his second phase, which boasts a more unpredictable AI, rapid-fire Godslayer fireballs, a teleporting charge attack, and the ability to turn invisible every now and then to bombard you with ''laser grids''.
* Jungle Dragon, Yharon. He packs enormous health, shaves off nearly half your health bar with each attack, moves incredibly quickly for his bulk, and punctuates his attacks with torrents of flares with varying movement patterns, BulletHell style barrages of fireballs (some of which he can immediately combo into a charge while you're still dodging), and flaming tornadoes to cut off your movement. He also limits your space to a small area cut off by flaming pillars, making excessive movement risky even discounting all the projectiles and tornadoes. This is compounded by the fact that he has so many distinct phases that it borders on ConfusionFu - if you don't account for each phase switching up his attacks, you'll almost certainly die due to how hard he punishes mistakes. And once he reaches his second full phase, he completely swaps out his previous attack pattern and fires even more wide-area projectile patterns in tandem with physical blows, even using TeleportSpam near the tail end of the fight just to trip you up.

* Polterghast. While its HP is on the low side, it deals extreme damage very quickly, slams players with a variety of highly lethal debuffs, and liberally spams beams that are rather hard to avoid. Worse still, while the instinctual response to a Plantera-esque boss would be to create a big arena to maneuver around it, Polterghast will actually get substantial attack and speed boosts the less tiles that are around it, meaning that making your arena too big may accidentally turn the boss into a full-on LightningBruiser - especially since it periodically use charge attacks that increases in intensity as it loses HP. Bursting it down is nigh-impossible since it has passive damage resistance that increases as it loses health. Since you have to fight it in the Dungeon and it can sometimes summon itself, you will be limited to a tiny area unless you set up an arena beforehand, and even then one has to be careful since the Polterghast TurnsRed depending on how open the space is. Taken to an absolute head in its final form as the Necroplasm - not only is it over twice as fast as before and able to deliver ridiculously strong melee attacks, now you have to contend with 3 deadly, invincible, mine-shooting Phantoms and a ''clone of the Polterghast'' that will launch coordinated charges with the boss itself.

* Supreme Calamitas, whose difficulty is downright notorious in the modded Terraria scene. The moment her fight begins, she'll build her own arena, go invincible, and unleash an omnidirectional, screen-spanning bombardment of ''hundreds'' of fireballs that deal stupendous amounts of damage, sometimes killing players before she even starts combat. Then, you'll have to handle Sepulcher, a large projectile-spamming worm that can only be killed by destroying the 10 deceptively durable Brimstone Hearts in the arena corners - preferably before Supreme Calamitas herself gets a chance to fire off too many attacks (killing the Sepulcher is even harder when one accounts for the fact that it can bodyblock for the Hearts). Then, when you actually fight her, it only gets worse: she's decently tanky, [[LightningBruiser blisteringly fast, deals enough damage to swiftly kill even defensive builds]], and spams all manner of projectiles like fireballs and explosive homing blasts which inflict lethal debuffs. Worse still, she'll pull off more tricks as the fight goes on, namely repeats of her first BulletHell survival phase with more projectiles gradually added in, summoning Supreme versions of her brothers that can flood the screen with shots, creating massive Brimstone Monster Orbs that chase players for the rest of the fight, creating dense rings of Soul Seekers to block attacks and rain hell, and even summoning the Sepulcher again near the end of her fight. All of these combine to make a brutally difficult, drawn-out fight where it's painfully easy to make mistakes, which is a bad thing when each one costs so much.

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* The Slime God. He's [[WakeUpCallBoss extremely difficult for the point of the game]] that you fight him at and is a large step up in difficulty from any of the bosses fought at the point. The Ebonian/Crimulan Slime Gods are prime examples of [[LightningBruiser Lightning Bruisers]]: they have decent bulk, powerful physical and ranged attacks that inflict devastating debuffs (Weak for the corruption slimes, Cursed for the Crimson slimes), very high mobility, armies of minions that spawn when they're damaged, and the ability to ''split into 2'' at half health. The large slimes will jump all over the place, soaking up hits while dealing ridiculous damage in return using their contact damage, minions, and fast shotgun sprays of slime balls. The Core itself isn't as much trouble at first, but it's small and sometimes hard to see in the chaos, not to mention that it can and will take potshots at you to inflict you with [[GravityScrew Distorted]] and [[DamageIncreasingDebuff Marked]], which can really ruin your day if one of the lesser Slime Gods are nearby. In addition, the Core can occasionally possess a larger God, jacking up its stats for a short time and letting it run you down. And depending on which God you kill first, the others will get unique buffs - woe betide you if you kill the Core first, which will turn the other two into even faster [[LightningBruiser Lightning Bruisers]] that practically teleport. And even if you go for the core last, you'll have to deal with its sudden increase in movement speed, teleportation, and spam of deadly aerial mines. Noteworthy is that the Slime God was voted fourth place in a community poll about who was the hardest boss despite being a pre-hardmode boss.
* Anahita and the Leviathan, albeit being more like an optional BonusBoss, are extremely difficult. It's a DualBoss fight against the GlassCannon Siren who is deceptively fast and hits very hard with both physical and ranged attacks that inflict StatusEffects, and the MightyGlacier Leviathan (which joins the fight once Siren is at 40% health) who is slow but incredibly bulky, takes up most of the screen, and deals ridiculous damage with both rams and boulder shots that shred defense, all while summoning minions. While they're normally fought one at a time, both bosses will become active simultaneously once the Leviathan is brought below 40% HP as well. Managing both bosses and the constant swarm of minions can prove to be extremely difficult, especially since Anahita and the Leviathan cover each other's weaknesses extremely well. Oh, and [[KillOneOthersGetStronger whichever one is the last one alive will become enraged]] (if you're on Death Mode, [[FromBadToWorse they both spawn in their enraged states]]). No wonder they were voted the fifth hardest bosses in the entire game.
* The Calamitas Clone. She's not too bad at first, although she can deal enormous damage and inflict the deadly Brimstone Flames debuff if you aren't careful. However, once you whittle her down enough, she'll summon a devastating HoldTheLine BulletHell that is guaranteed to take you down a few pegs if you aren't prepared, before adding in lightning-fast charges to her previous attacks. The real problem arises when she summons her brothers later on; Catastrophe and Cataclysm are extremely fast, do tons of damage, and use flamethrower/bouncing fire attacks that take up huge portions of the screen. Even if you figure out how to dispatch the brothers, you'll have ''another'' bullet-hell segment to deal with before Calamitas goes berserk and resorts to nonstop ramming.
* The Plaguebringer Goliath, a LightningBruiser with very high HP, study DR, incredible amounts of mobility (sometimes charging ''diagonally'', something that can trip up players expecting a Queen Bee clone), and a combination of deadly contact damage and extremely powerful projectile spam. Her attacks all inflict the Plague debuff, which can be annoying at best and lethal at worst. She also punctuates her own attacks with waves of deadly minions, which include Plague Seeker swarms, homing missiles that explode, and invincible Plague Mines that deal huge area damage on contact (Expert+). The second part of the fight on Expert+ is even worse, as she now rains down missiles as she charges - not to mention that she'll gradually get stronger as you wear down her health bar.
* Ravager quickly became this after receiving a massive rework. It has a colossal amount of health, deals stupidly high damage, and has a wide variety of attacks to hammer you with, including fireballs, homing flares, heat-seeking missiles, giant rock pillars, flaming lanterns that shoot fireballs at you, and of course its physical attacks. All of these attacks will usually stack together to make patterns almost impossible to dodge. During its second phase, not only is it capable of terrifyingly fast, predictive jumps to slam down on players, it pulls out a few new tricks - not only is its head also chasing you around and vomiting even more projectiles than usual, you ''permanently have your flight time decreased by 50%''[[note]]And before you even think of it, it disables extra jumps and jump height boosts as well[[/note]], forcing you to stay (mostly) grounded and face the brunt of Ravager's attacks.

* The [[ClimaxBoss Devourer of Gods]] is downright ''infamous'' for being this. He's massive, has obscenely high health, moves incredibly fast, and deals insane damage with just about every attack on top of inflicting God Slayer Inferno, ''especially'' upon contact: enough that getting hit by its head in will more often than not result in instant death. Standard worm tactics with piercing weapons? Does next to nothing since anything that's not its head or tail takes next to no damage. Thought you could just build a platform in the sky to deal with it like you did with Destroyer? Well, too bad it doesn't need solid blocks to move. Try and outrun it? Not only does it fire long-ranged laser bursts which occasionally take on unconventional patterns, it will '''always''' be faster than you. Mobility? Neutered since just being near it warps gravity and flight. And it gets taken up a notch further in Revengeance mode: not only is it even more powerful than before, it can summon Cosmic Guardians at certain HP intervals, which hunt down the player like seeker missiles and deal ridiculous damage on contact (although piercing weapons make short work of them). Still not enough for you? Well, when you beat him down a bit, he summons his Sentinels (albeit weaker versions unless you haven't beaten them yet, and only before you've beaten them once), forcing you to fight them right after each other. Kill those, and he ''comes back'' with even more health, a more unpredictable AI, rapid-fire Godslayer fireballs, a teleporting charge attack, and the ability to turn invisible every now and then to bombard you with ''laser grids''.
* Jungle Dragon, Yharon. He packs enormous health, shaves off nearly half your health bar with each attack, moves incredibly quickly for his bulk, and punctuates his attacks with gigantic fire blasts, BulletHell style barrages of fireballs, and flaming tornadoes. Not to mention that he limits your space to a small area cut off by flaming pillars, making excessive movement risky. His second phase where he switches out his AI and is even worse, as he'll start spamming all manner of projectiles in tandem with physical blows, and using TeleportSpam as his attacks gradually build in intensity.
* Supreme Calamitas, whose difficulty is downright notorious in the modded Terraria scene. The moment her fight begins, she'll build her own arena, go invincible, and unleash an omnidirectional, screen-spanning bombardment of ''hundreds'' of fireballs that deal stupendous amounts of damage, sometimes killing players before she even starts combat. Then, you'll have to handle Sepulcher, a large projectile-spamming worm that can only be killed by destroying the 10 deceptively durable Brimstone Hearts in the arena corners - preferably before Supreme Calamitas herself gets a chance to fire off too many attacks (killing the Sepulcher is even harder when one accounts for the fact that it can bodyblock for the Hearts). Then, when you actually fight her, it only gets worse: she's decently tanky, [[LightningBruiser blisteringly fast, deals enough damage to swiftly kill even defensive builds]], and spams all manner of projectiles like fireballs and explosive homing blasts which inflict lethal debuffs. Worse still, she'll pull off more tricks as the fight goes on, namely repeats of her first BulletHell survival phase with more projectiles gradually added in, summoning Supreme versions of her brothers, creating massive Brimstone Monster Orbs that chase players for the rest of the fight, creating dense rings of Soul Seekers to block attacks, and even summoning the Sepulcher again near the end of her fight. All of these combine to make a brutally difficult, drawn-out fight where it's painfully easy to make mistakes, which is a bad thing when each one costs so much.
* Supreme Calamitas' alternate equivalent, the Exo Mechs, are just as bad if not worse. They're a WolfpackBoss fight against the four titular Mechs that are extremely threatening individually, but will eventually gang up on you and combine their strengths to create an absurdly difficult attacking formation. Artemis and Apollo are two very fast fliers who constantly use evasive maneuvers to dodge incoming attacks while using devastating projectiles and charges, and Thanatos is an enormous worm who obstructs your movement and unleashes BeamSpam while also only being vulnerable while shooting. Ares is arguably the worst of them all, as it has four independent weapons that deal massive damage in wide areas, particularly its WaveMotionGun and FantasticNuke that can instantly end you if you're not careful. They're manageable at first due to their heavily deterministic attacks, but once all of them start fighting together and pinning you from multiple directions, managing all of them simultaneously becomes a chaotic nightmare where failing to keep track of all of the attacks will incur massive damage - and there are a ''lot'' of attacks to keep track of. Worse still, all of their attacks lead your movement, so just running away will often get you killed. Although doing enough damage eventually causes the damaged Mech to fight you one on one, they'll enter a second phase when alone which enhances their attacks and gives them new tricks: Thanatos spams even more lasers and starts using a WaveMotionGun that is nearly impossible to throw off unless you stay near its head, Artemis and Apollo start to desync their enhanced attacks while using a massive laser and explosive charge combos respectively, and Ares fires faster and can trap the player in a rotating cage of devastating rays while raining fire. And just to add insult to injury, the [[KillOneOthersGetStronger last mech alive will go absolutely berserk]].

** If you fight her at night, you'll get a chance to battle her in an [[UpToEleven even stronger state]] that dials all her stats up to an insane degree and empowers all her attacks, in exchange for dropping exclusive items.

* Much like the original Duke Fishron, the Old Duke is a real hair-puller. He takes the Duke's LightningBruiser aspects and turns them UpToEleven - packing high HP, very sturdy damage reduction, lightning-fast speed and ''insane'' damage, on top of flooding the screen with projectiles/hazards and inflicting all manner of StatusEffects on hit. To make things worse, his charge attacks strongly predict player movement, so if you don't make more evasive maneuvers to throw him off he ''will'' hit you. Fortunately, he'll stop to rest every 10 attacks and temporarily drop his defenses to zero, but more often than not the opportunity to attack will be squandered just trying to recover from his prior beatings.
* The [[ClimaxBoss Devourer of Gods]] is downright ''infamous'' for being this. He's massive, has obscenely high health, moves incredibly fast, and deals insane damage with just about every attack on top of inflicting God Slayer Inferno, ''especially'' upon contact: enough that getting hit by its head in will more often than not result in instant death. Standard worm tactics with piercing weapons? Does next to nothing since anything that's not its head or tail takes next to no damage. Thought you could just build a platform in the sky to deal with it like you did with Destroyer? Well, too bad it doesn't need solid blocks to move. Try and outrun it? Not only does it fire long-ranged laser bursts which occasionally take on unconventional patterns, it will '''always''' be faster than you. Mobility? Neutered since just being near it warps gravity and flight. And it gets taken UpToEleven in Revengeance mode: not only is it even more powerful than before, it can summon Cosmic Guardians at certain HP intervals, which hunt down the player like seeker missiles and deal ridiculous damage on contact (although piercing weapons make short work of them). Still not enough for you? Well, when you beat him down a bit, he summons his Sentinels (albeit weaker versions unless you haven't beaten them yet, and only before you've beaten them once), forcing you to fight them right after each other. Kill those, and he ''comes back'' with even more health, a more unpredictable AI, rapid-fire Godslayer fireballs, a teleporting charge attack, and the ability to turn invisible every now and then to bombard you with ''laser grids''.

* Much like the original Duke Fishron, the Old Duke is a real hair-puller. He takes the Duke's LightningBruiser aspects and turns them UpToEleven - packing high HP, very sturdy damage reduction, lightning-fast speed and ''insane'' damage, on top of flooding the screen with projectiles/hazards and inflicting all manner of StatusEffects on hit. To make things worse, his charge attacks predict player movement, so if you don't make more evasive maneuvers to throw him off he ''will'' hit you. Fortunately, he'll stop to rest every 10 attacks and temporarily drop his defenses to zero, but more often than not the opportunity to attack will be squandered just trying to recover from his prior beatings.

* Supreme Calamitas, whose difficulty is downright notorious in the modded Terraria scene. The moment her fight begins, she'll build her own arena, go invincible, and unleash an omnidirectional, screen-spanning bombardment of ''hundreds'' of fireballs that deal stupendous amounts of damage, sometimes killing players before she even starts combat. Then, you'll have to handle Sepulcher, a large projectile-spamming worm that can only be killed by destroying the 10 deceptively durable Brimstone Hearts in the arena corners - preferably before Supreme Calamitas herself gets a chance to fire off too many attacks (killing the Sepulcher is even harder when one accounts for the fact that it can bodyblock for the Hearts). Then, when you actually fight her, it only gets worse: she's decently tanky, [[LightningBruiser blisteringly fast, deals enough damage to 2 or 3-shot even endgame players]], and spams all manner of projectiles like fireballs and explosive homing blasts which inflict lethal debuffs. Worse still, she'll pull off more tricks as the fight goes on, namely repeats of her first BulletHell survival phase with more projectiles gradually added in, summoning Supreme versions of her brothers, creating invincible Brimstone Monster Orbs that chase players for the rest of the fight, creating dense rings of Soul Seekers to block attacks, and even summoning the Sepulcher again near the end of her fight.
* Supreme Calamitas' alternate equivalent, the Exo Mechs, are arguably even worse. They're a WolfpackBoss fight against four obscenely powerful bosses that are extremely threatening individually, but will eventually gang up on you and combine their strengths to create an absurdly difficult attacking formation. Artemis and Apollo are two very fast fliers who constantly use evasive maneuvers to dodge incoming attacks while using devastating projectiles and charges, and Thanatos is an enormous worm who unleashes BeamSpam while also only being vulnerable while shooting. Ares is arguably the worst of them all, as it has four weapons that deal massive damage in wide areas, particularly its WaveMotionGun and FantasticNuke that can instantly end you if you're not careful. They're manageable at first, but once all of them start fighting together and pinning you from multiple directions, managing all of them simultaneously becomes a chaotic nightmare where every attack deals massive damage - and there are a ''lot'' of attacks to get hit by. Worse still, all of their attacks lead your movement, so just running away will just get you killed. Although doing enough damage eventually causes the damaged Mech to fight you one on one, they'll enter a second phase when alone which enhances their attacks and gives them new tricks, with the [[KillOneOthersGetStronger final mech left in particular]] going absolutely berserk.

* The Slime God. He's [[WakeUpCallBoss extremely difficult for the point of the game]] that you fight him at and is a large step up in difficulty from any of the bosses fought at the point. The Ebonian/Crimulan Slime Gods are prime examples of [[LightningBruiser Lightning Bruisers]]: they have decent bulk, powerful physical and ranged attacks that inflict devastating debuffs (Weak for the corruption slimes, Cursed for the Crimson slimes), very high mobility, armies of minions that spawn when they're damaged, and the ability to ''split into 2'' at half health. The large slimes will jump all over the place, soaking up hits while dealing ridiculous damage in return using their contact damage, minions, and aerial mines, some of which linger for stupidly long amounts of time and clutter the battlefield. The Core itself isn't as much trouble at first, but it's small and sometimes hard to see in the chaos, not to mention that it can and will take potshots at you to inflict you with [[GravityScrew Distorted]] and [[DamageIncreasingDebuff Marked]], which can really ruin your day if one of the lesser Slime Gods are nearby. In addition, the Core can occasionally possess a larger God, jacking up its stats for a short time and letting it run you down. And depending on which God you kill first, the others will get unique buffs - woe betide you if you kill the Core first, which will turn the other two into even faster [[LightningBruiser Lightning Bruisers]] that practically teleport. And even if you go for the core last, you'll have to deal with its sudden increase in movement speed, teleportation, and spam of deadly aerial mines. Noteworthy is that the Slime God was voted fourth place in a community poll about who was the hardest boss despite being a pre-hardmode boss.

* Providence provides a first impression of what the endgame is like in Calamity, and serves as a harsh gatekeeper for many a player trying to get into the post-Moon Lord segment of the game. She is extremely bulky, deceptively fast, and shaves off enormous amounts of health with each attack, using an incredibly wide and varied arsenal of projectiles to harass you with. Her attacks are all tricky to avoid, inflict a potent DamageOverTime debuff, and tend to [[BulletHell flood the screen with projectiles]] (particularly those where she goes stationary and launches a bullet-hell attack), and some of them even use gimmicks to screw you over (such as ''inflicting negative healing to completely ignore armor and invulnerability frames''). As you lower her HP, she'll spam these attacks gradually faster while adding more to her arsenal, like an invincible crystal that rains harmful shards, a devastating WaveMotionGun that would put Moon Lord to shame, or even ''[[DegradedBoss summoning weaker versions of the Profaned Guardians]]'', one of which ''heals her''. And the icing on the cake is that she can inflict a debuff that greatly weakens your flight, in a fight where mobility is likely your best chance at survival.