Note: Because of the sandbox nature of Terraria, it is very much possible to cheese many of the bosses on this list with proper prep-work. As such, bosses listed here are based on the bare minimum amount of setup needed to have a chance at fighting them. Do not list ways to cheese bosses on this list; TV Tropes is not GameFAQs.
Note: Superbosses are excempt from being That One Boss. They do not block progress, so players can just skip them if they cannot defeat them.
open/close all folders
Pre-Hardmode Bosses
- Surprisingly, the Eye of Cthulhu is tricky on Expert, mostly due the extra-fast charge it'll start using in its second phase. It's incredibly fast, deals obnoxiously high damage, and will likely be near-impossible to avoid at the level you're supposed to be fighting the Eye at. When it's at critical health, it'll be doing it constantly - good luck hitting it with arrows.
- Skeletron can be a pain to beat. First off, he has significantly more health than the other Pre-Hardmode bosses, and boasts two Cognizant Limbs which will flail around and do respectable amounts of damage on hit. Secondly, he resists the majority of Damage Over Time debuffs, so unless you made Frostburn Arrows, you're tough out of luck. Thirdly, he can perform a head charge which is not only difficult to dodge at this point in the game, but can easily stunlock you and hammer you for a ridiculous amount of damage. Not to mention that the way his spawning works means that he's guaranteed to spawn on top of you, nailing you for cheap damage if you're unlucky. Should dawn arrive due to poor timing or the fight taking too long, Skeletron will instantly kill you. All of this is cranked up to eleven in Expert Mode - not only does he have more health than Normal Wall of Flesh, he inflicts Status Effects, is Nigh-Invulnerable until you take down both his hands, and can vomit out dangerous homing projectiles at an alarming rate, all the while massively increasing the speed of his aforementioned head charge.
- Wall of Flesh. If you don't prepare yourself in a ridiculous manner before the fight, you will have a LOT of trouble. First, you have to contend with the Hungry, mouths on tentacles that do ridiculous melee damage and become flying critters when killed, forcing you to kill them twice. For added annoyance, they respawn on Expert. They make ranged weapons a problem to use (unless you use Meteor Bullets or Unholy Arrows). If you get past that, you still have to deal with the Wall itself, which has very high health and uses Beam Spam from both eyes with increasing frequency as you do damage. On top of that, it accelerates as it takes damage; to the point where on Expert difficulty, the Wall actually becomes faster than the player at full sprint when on its last legs,. NO strategy will assure success against that freaking wall. Which makes coming back with Hallowed Armor, the Megashark, Crystal Bullets, and Excalibur (or, heaven forbid the Zenith) for round 2 (or whatever number fight it is) all the more satisfying. Adding to this is the fact that it's prone to bugs. It may accidentally spawn heading the wrong way, which is pretty much instant death because any prepared player will summon it at the far end of the map. It can also spawn much further down than it's supposed to, making the world-spanning bridge you're basically required to build if you don't want to spend 90% of the fight swimming in lava or jumping over pits and structures useless. There's a reason why the characters' page says there's no middle ground - you're either overprepared or dead.
Hardmode Bosses
- The Destroyer is widely considered to be the easiest of the Mechanical Bosses, but that doesn't mean it's easy. It was briefly nerfed in 1.2 reducing its defense, damage, and health, but then 1.2.3 came along and reversed the nerf big time, raising its stats even higher than they were before. Additionally, there's less healing for you during the fight (since probes now only drop hearts 33% of the time instead of 100%) and it's completely immune to all debuffs! Most strategies that would have instantly killed Destroyer before are now significantly less useful, and you'll have to contend with its massive health bar, Beam Spam, and storm of minions without those prior tricks. However, piercing weapons (most infamously the Daedalus Stormbow/Holy Arrows combo) can still take it down very quickly, and targeting its coiled segments when it first spawns can outright end the fight in seconds.
- The Twins are a Dual Boss that can easily box you in with little effort thanks to their huge hitboxes, incredibly fast speed which makes dodging them very tricky, and their Turns Red mode that takes their attacks up a notch. Spazmatism has a cursed flame attack in his panic mode with a ridiculously huge hitbox, and charges at you with barely a second to dodge. Meanwhile, Retinazer's Eye Beams start getting spammed to Bullet Hell levels. The only reliable strategies many players can cook up is "make a giant sky bridge that extends all the way across the world, shoot at Spazmatism while running away on a fast mount", or "use Gravitation potion and keep switching gravity as you run away from the Twins and shoot at Spazmatism".
- Skeletron Prime if you're trying to beat him solo. He has four arms, each of which has its own abilities and can do a fair amount of damage, and his head gains defense when it spins instead of losing it like the last version did. His high health and arms will soak up damage to near the end of the night if you don't have high DPS or piercing weapons, and if you don't beat him by then, he becomes practically unbeatable and gets a One-Hit KO attack.
- Plantera provides a large Difficulty Spike compared to the mech bosses. She has a ton of HP, and she shoots petals (homing in Expert) and spiked balls that do a lot more damage, but if you prepared for her with an arena, then her first form is basically a cakewalk. All that changes when she gets down to half health. She goes berserk, doubles in speed (sufficient to outrun a player wearing Lightning Boots and using a Swiftness potion) and deals even more damage. For added measure, Chlorophyte homing bullets will be negated by the Combat Tentacles she spawns in her second phase, which forces you into either using melee attacks or switching to different bullets and hoping you can get enough shots through. And don't even think of going to the overworld jungle to get the advantage— doing so will cause her to become enraged and double her damage, defense and speed.
- Of all the Celestial Pillars, the Solar Pillar is infamous for how hard it is, and on Master difficulty it's absolutely sadistic. The Solar Pillar is designed to enforce melee with its special mechanics, but melee is suicide on Master difficulty due to the sheer amount of damage everything does - Everything will kill you in 2-3 hits. If you bring a ranged weapon or a magic weapon, Selenians will reflect your projectiles back at you so you hit yourself. If you try flying or multi-jumping, Crawltipedes will spawn and seek you out no matter how fast you fly or how far away you go and will deal 450-500 damage if they hit you. If you stand on the ground, you will have to deal with Srollers launching themselves at you from offscreen at incredible speeds. Try to hide behind blocks? Corites ignore them. And the pillar itself will randomly throw a half-dozen fireballs at you while you do all this. The greatest irony is that this supposedly melee-themed pillar has the largest, fastest, and most frequent 'projectiles' of any of them because of all the mobs throwing themselves at you. Most peoples' advice for beating the Solar Pillar on Master is just 'Keep throwing yourself into it and respawning and it will eventually die.' It's often considered harder than the Moon Lord.
Events
- The Martians are already a piece of work, but the boss of the event, the Martian Saucer, turns it up. It has a hefty amount of health split over its 5 parts, is faster than it looks, and deals extremely high damage with a wide variety of hard-to-dodge attacks, including a death ray that hits hard, passes through walls post-Journey's End update, and can chunk you for up to 200 damage on Expert. And on Expert, if you think you've got it on the ropes after taking down its weapons to disable its Beam Spam and Macross Missile Massacre attacks, then think again, because not only does it now have a defense of 100, all but nullifying low-power weapons, it'll dash all over the place while spamming its Wave-Motion Gun, which now deals over double the damage it used to and is liable to deliver two-hit kills.
