* AlternativeCharacterInterpretation: There has been discussion about whether the player character is a VillainProtagonist. After all, while there are bosses who attack without provocation (like the Eye of Cthulhu and the three mechanical bosses), most bosses need to be summoned with an item. Others, like Queen Bee or Plantera, only attack after the player destroys their progeny. Are they truly malevolent, or just victims of a BloodKnight who destroys everything in his or her path?
* AnticlimaxBoss:
** While the Golem is a strong boss, it's disappointing for many players who see it as much easier than Plantera, the boss coming immediately before it. Demoted to BreatherBoss between Plantera and Duke Fishron as of version 1.2.4.
** The [[spoiler:Moon Lord]] himself can turn out to be this, depending on your strategy. If you wear Tiki Armor or Spider Armor and summon a Stardust Dragon (with the staff crafted from the appropriate pillar's fragments), then hide in a small house with your nurse, you can just sit there for a minute or two getting healed repeatedly while your dragon kills him for you.
** The Martian Saucer can be this for similar reasons. Unlike the [[spoiler: Moon Lord]] though, ''none'' of it's attacks go through walls. The only damage it can do to you while in a building is splash damage from explosions. Set yourself up in a big enough box, summon your minions outside it, and watch as you get the Cosmic Car Key in record time.
** With proper preparation and thanks to the ability to create custom arenas, ''any'' of the bosses in the game can easily become this. Many players have come up with ways to AFK every boss in the game, most of which can be done before even fighting the boss properly.
* BaseBreaker: The Guide. Either he's a clueless asshole who will happily open doors to let zombies and the like into your house to ruin your early game, or he's a helpful and kind tutor who is the reason you've managed to avoid GuideDangIt for a while and deserves some slack. As a result, [[spoiler:summoning the Wall of Flesh by destroying the Guide via a voodoo doll]] comes with reactions ranging from "I have to [[spoiler:''kill him'']] to proceed in the game?!" to "Ha, TakeThatScrappy".
* BreatherBoss: The Golem. It does have some dangerous attacks and a lot of HP, but it's also fairly predictable and much easier to fight than Plantera, the boss you had to defeat just to reach the Golem. It also helps that it can't pass through blocks, meaning you can run into the hallway, rendering the Golem useless.
* BrokenBase:
** Terraria version 1.0.6 quickly became one of the most polarizing updates in its history due to a few high caliber bugs that made it into the game.
** One of the more annoying changes is the inability to place anything in lava anymore, meaning that making tunnels to Hell are much harder to create now unless you exploit dropping sand into the lava or are really patient about using water to make obsidian walls or digging a reservoir to drain the magma into. Since mining Hellstone creates lava now, this makes Hellstone difficult to mine without lava-immunity potions or digging a reservoir below to carefully drain the magma into.
*** 1.2 however gave us boots that allowed the player to walk on water. If you somehow got your hands on Lava Charm and Obsidian, you could combine the the boots with Obsidian and then the resulting boots with the Lava Charm. That would give you not only the ability to walk on fire tiles and walk on lava surface, but also the ability to sink into the lava for 7 seconds. Equip a Lava Charm with these boots as well and you will be able to stay in the lava for fourteen seconds.
** The release of 1.0.6.1 corrected the bugs and fixed the fireblossom issue, but it got broken again when 1.1 made it so not even the sand trick worked anymore.
** The announcement marking the end of Terraria's development after one last bugfix has broken the base into those who think Terraria is ruined, those who just accept that all things come to an end ultimately, and those who believe that the real experience [[AndTheAdventureContinues has just begun]], and its time for {{Game Mod}}s to shine.
*** Subverted; more updates followed later on.
** When the announcement was made that XBLA and PSN versions of the game were being developed and that they would feature new content, the majority of the old PC crowd [[{{Understatement}} were not pleased]] to say the least, especially because this news was hyped up the day before after months of silence.
*** The console version. RuleOfCautiousEditingJudgment would be in effect.
** Medusas. Are they a cool and unique, [[DemonicSpiders if unusually dangerous]] enemy that forces you to switch up your strategy and adds a level of coolness to the game? Or an obnoxious {{Fake Difficult|y}} gimmick enemy that exists only to screw you over? The nerf they got in 1.3.0.4 calmed this argument slightly, but the medusas still have their share of haters.
* CatharsisFactor: The game becomes quite relaxing once you get end-game equipment, being able to build with little/no worry since anything that disturbs you or your [=NPCs=] are generally reduced to dust with your weapons.
* ComplacentGamingSyndrome:
** Pre-version 1.2.: It's rare to see people use anything other than the Minishark, Megashark, swords, and Crystal Storm.
** Post 1.2.: Vampire Knives, Shadowbeam Staff, and Spectre Armor with Spectre Hood are all but essential for endgame bosses. And then this is turned around against the Moon Lord; it gives a debuff that prevents the life-stealing effect from working.
** Hello, Solar Eruption. Put simply, this is a weapon that everybody, no matter their build, should consider getting in their inventory once they hit the end game. It's very affordable to craft, being made only from the drops of a lunar pillar and thus not requiring the final boss to get at, and so can very easily gotten by everybody. To put it simply, it's a melee weapon with crazy reach, hits enemies through walls, and is one of the most powerful weapons due to being made of end game material. Not only does it hit through walls, but it will also light up wherever it goes.
* DemonicSpiders: [[DemonicSpiders/{{Terraria}} So many of them, they got their own page]].
* FandomRivalry: With ''VideoGame/{{Minecraft}}'', and to a lesser extent, ''VideoGame/{{Starbound}}'', due to both games having similar elements.
* FridgeLogic: Bones can drop from Skeleton warriors in the dungeon, but not the random skeletons you find underground. Justified for game balance; bones themselves are a decent ranged weapon, and they can be made into Necro Armor, which is a ranged-based set of armor that increases damage and reduces ammo consumption.
** Which may be explained by the skeleton's appearance. Its bones are green, and probably worn away from underground [[BuffySpeak dampness or something]].
* GameBreaker: Enough to [[GameBreaker/{{Terraria}} warrant its very own page.]]
* GoddamnedBats:
** As you get better gear, previously challenging monsters go from threats to annoyances, but they still cause knockback even if they cause no appreciable damage. Even after you have a full set of Molten armor you can still be killed by a lowly slime slapping you into a pit of lava. That is, unless you have a Cobalt Shield or its upgrades to prevent knockback, in which case they go from a minor threat to practically nothing.
** ''Any'' enemy if you're trying to manage your items or craft something, especially worms.
** Want to get your hands on some Meteorite? You'd better have the patience of a saint, since Meteor Heads will be constantly harassing you as you try to pick it up.
** The game has literal bats, and though they aren't that dangerous as long as you have good armor (save the Giant Bats in Hardmode that confuse you), they spawn ''constantly''. On top of that, their hit-box is a single block, so ranged weapons have a hell of a time scoring a hit. This is especially true in the Underworld, where up to five at a time may be harassing you, and down there they do enough damage that even Molten armor isn't enough to render them harmless. Considering you have to spend a not-insignificant amount of time down there trying to flatten the place out for the Wall of Flesh, this can get old fast. In Expert, they're ''even more annoying''--getting hit by them can give you the Feral Bite debuff, which increases your damage, lowers your regeneration... and also periodically gives random smaller debuffs on you, such as Confusion. It takes an entire minute to wear off.
** Spellcaster monsters have the ability to teleport to random locations near you and fire through walls. Though the projectile can be destroyed by a single hit from any weapon, they'll harass you until you chase them down and kill them, which only takes a few hits once you get there. This often means digging holes in every direction since they decided to teleport somewhere you can't reach. Fire Imps, the underworld variant, are even worse. The underworld is at least 75 percent lava at surface level, and all the good hellstone deposits require digging through the towers spaced between the lakes. This means the Imps often appear in out-of-reach places. They can and will show up when you're busy fighting Bone Serpents or mining. Oh, and unless you came with an Obsidian Skin potion or a Lava Charm/Waders, you have to deal with this on top of avoiding the lava and possibly not burning yourself on the ore. [[SarcasmMode Have fun]]!
** Harpies. Flying enemies that appear at high altitudes and use a high damage projectile feather attack that shoots out multiple projectiles. Doubly so if you're trying to fish up there.
** Archers are annoying as heck. The hit you from a long way away, do hefty damage, and the Skeleton variant can set you on fire.
** Underworld has the Lava Slimes. They jump far and fast and literally leap off of lava like a spring. In Expert mode, they drop a block of lava when killed.
** The various Eaters in the Corruption, because they just never stop coming and spawn really quickly. The Crimson is better because its variant spawns less frequently.
** Gastropods shoot pink lasers from off screen with ridiculous speed and accuracy and deal massive damage for a common mob. Plus, they tend to gang up on you.
** Chaos Elementals run like crazy, charging you and teleporting all over the place.
** For a new player or someone setting out with a new character, Flying Fish are difficult to deal with due to their numbers.
** The Lunar Event is ''chock-full of them''. Most of them also have a great amount of health, requiring the strongest weapons to bring down.
*** Nebula Pillar: Brain Sucklers appear in huge numbers and fly straight at you, even through walls. When they hit you, they latch onto your head and greatly obscure your vision and deal a good amount of continuous damage. Nebula Floaters fly around, fire painful projectiles, have a good amount of health and teleport when hit.
*** Stardust Pillar: Star Cells are {{Asteroids Monster}}s that, when killed, produce four smaller cells which can each grow into a new Star Cell, creating a potentially endless swarm if you can't track down the cells or don't have a weapon that deals damage over time like fire. (However, since progression through the event depends on the number of enemies you kill, Star Cells can be used to block any other spawns and make progression very easy, provided you can avoid them.) Milkyway Weavers can pass through walls and can appear in numbers.
*** Solar Pillar: Corites, Srollers, and Selenians. All three appear in numbers, the first performs a homing fireball tackle that deals good damage and passes through walls, the second and third perform a rolling attack that doesn't pass through walls or home in, but hurts even more, and the Selenian's rolling attack ''[[SpinToDeflectStuff deflects projectiles]] [[AttackReflector back to you]]''. And if one attempts to avoid them by flying... the [[DemonicSpiders Crawltipedes]] are there to [[AntiAir make sure you]] ''[[AntiAir don't]]''.
*** Vortex Pillar: Storm Divers can fly around, and fire a very painful shotgun attack that can be tricky to avoid. Thankfully it's easy to hide from them behind terrain and use a penetrating weapon to beat them. Alien Queens spit a projectile that causes the Distorted status, causing the player to float about uncontrollably. Finally, Alien Hornets can sometimes be spawned right on top of you by the pillar for cheap CollisionDamage.
* GoddamnedBoss:
** A number of bosses like to alternate between floating out of melee range and ramming the player to death, requiring the player to keep a projectile weapon and stay out of these bosses' range.
** If you ''do'' have a Warmth Potion and sufficient armor, then the Ice Queen of the Frost Moon turns into this. She flies around the area very quickly, making it ''very irritating'' to get a good hit on her. Furthermore, she has lots of health, so expect her dodging and flying around to prolong the fight. However, her attacks won't deal that much damage due to the Warmth Potion weakening them. ''Without'' a Warmth Potion or sufficient armor, she becomes ThatOneBoss.
** The Lunatic Cultist. He liberally uses TeleportSpam and uses DoppelgangerAttack while floating around and casting annoying-to-avoid spells. Being human-sized, he also has a very small hitbox for a boss. Thankfully, he doesn't move whenever he's casting, as well as the fact that he holds a particular weakness to [[HomingProjectile chlorophyte bullets.]]
** The Queen Bee can be quite annoying for players who accidentally destroyed her larva. One of her most annoying attacks is her charging attack, which can take away a good amount of your health, and after that, she starts shooting destroyable bees that can poison at you like bullets or even ''more'' annoying ''indestructible'' rapid-fire poison stingers. But if you manage to defeat her, the rewards are worth the fight, since she drops some pretty good pre-Hardmode weapons and armor.
* GoodBadBugs:
** Examples which are still "at large":
*** Fluid dynamics are completely broken, allowing you to create automated generators that create unlimited amounts of lava and water out of thin air, which in turn allows you to mine unlimited amounts of obsidian, which you can then turn into an unlimited number of obsidian skulls, which you can then sell for an unlimited amount of money. Basically, once you obtain a bucket of lava, your wealth is only limited by your patience.
*** Minimizing the program in a certain way causes it to run ridiculously fast in the background. This is handy if you want to park somewhere safe and wait for nightfall/daybreak, or if you've set up an automated monster-farming trap and want to wait for a bunch of RandomDrops.
*** The differences between water and air pressure is ignored, so you can dive 300 meters underwater, dig a small tunnel, then dig up a bit into a roomy cavern, and the cavern will not get wet at all (to get the idea, imagine a J-shaped test tube that can fill all the way up on the right side without the left side overflowing).
*** During the Blood Moon, zombies can bash doors open, but only inward. Putting something that occupies the space but doesn't have collision (a cloth banner or another door, open in the opposite direction, for example) will make the door impossible to open inward, meaning that you can come and go freely but the zombies won't get in. It should be noted, however, that goblins don't have this problem as they bash doors ''completely off the hinges''.
*** With [[{{MenuTimeLockout}} autopause]] turned on, you can swing your sword and pause in the middle of the animation to click a potion up from your inventory, unpausing will consume it, ''even if you have the Potion Sickness debuff that would have prevented you from consuming it in the first place''.
*** Light Discs, the Dao of Pow, and the Shadowbeam Staff, if used in just the right way, can actually glitch through one-block-thick walls.
*** After the 1.2 Big Update, it is possible for worldgen to create a Lihzahrd Temple in the Jungle with a messed-up layout that allows you entry into the Temple without having defeated Plantera and getting the Temple Key to unlock the door.
*** After the 1.3 Big Update, it is possible for worldgen to accidentally generate a Granite or Marble Cave mini-biome that overlaps part of the Lizhard Temple, similarly allowing you to break sequence and enter it long before beating Plantera.
*** An interesting and much-exploited collision detection/clipping/zipping bug that was introduced by the sloped blocks in the 1.2 Big Update has been dubbed the [[http://www.terrariaonline.com/threads/hoik-guide-rapid-player-npc-etc-transport-using-only-sloped-tiles.160618/ "HOIK"]]. Yrimir has demonstrated this bug by [[https://www.youtube.com/watch?v=iHw06h2L-rc slaying the Dungeon Guardian]] with a HOIK setup that allowed him to attack it with impunity while zipping around it in a circle. WordOfGod has confirmed that no specific efforts will be made to fix the hoik glitch.
*** The Lihzahrd altar can spawn directly below a low ceiling on world generation, which completely immobilizes the Golem's main body when summoned by the fact that the golem spawns directly above the altar and main body cannot move through rocks. Assuming you can still get a clear shot at the body in this state and damage it, the fight becomes laughably easy since it eliminates much of the need to dodge the main body's attacks, allowing you to pick off the body parts at your own pace.
** Examples which have been "fixed":
*** Prior to 1.1.1, trying to place a recorded music box on a table would duplicate the item by a massive amount, these boxes sell for two gold ''each''.
*** Like all bosses the Eater of Worlds flees if he kills the player and there are no other players nearby to challenge him. Prior to 1.0.6 the Eater of Worlds was considered ''slain'' when he fled complete with full drops, allowing you to run back to the battlefield and collect its loot.
*** Early after the 1.2 Big Update, canny players were able to use Actuators to force Lihzahrd Bricks into the background, allowing access to the Lihzahrd Temple without beating Plantera and getting the Temple Key. This was soon fixed. Likewise, they used to be able to use a Teleporter to bypass the door. Both of these were 'fixed' by making it so that Teleporters and Actuators could not work in the Lizhard Temple biome ''until'' you defeat Plantera.
*** Version 1.2.4 added some amusingly overpowered acceleration mechanics with the Minecart's physics, allowing players to accelerate their carts to such an insane velocity that they can either get sent flying thousands of blocks away, accidentally get noclipped through terrain blocks out to the middle of nowhere, or sometimes even deal thousands of points of damage to any enemies or bosses their minecarts run through when blazing away at such ludicrous speeds. This bug has been fixed as of 1.2.4.1, much to the disappointment of a number of players who were exploiting this trick.
* JunkRare:
** Played straight with the Enchanted Sword, a rare sword with the ability to fire damaging energy beams with each swing. It is one of the most rare items in the entire game. The game has a small chance of spawning the Enchanted Sword somewhere underground when you first generate a world. There is no indication that the sword has spawned and since it's in a random spot underground you could potentially spend a thousand hours in a world with an Enchanted Sword and never know it's there. In the off chance that you do somehow manage to find an Enchanted Sword you realize that... it's terrible. It has only one point of damage more than the Light's Bane, a low tier weapon. The ability to fire energy beams isn't even all that special, even pre-Hardmode. The Ice Blade, another pre-Hardmode weapon, does the same thing, is almost as damaging, and is far easier to acquire.
*** No longer as bad after 1.3, where Enchanted Sword shrines can spawn, with a 3/10 chance that the sword is the Enchanted sword (and a 1/30 where it is a Arkhalis)
** {{Exaggerated|Trope}} with the Slime Staff. It has the lowest drop rate of any enemy-dropped item: only a 1 in 10,000 chance, and even Pinky only has a 1% chance to drop it. This makes it potentially the rarest of any of the summon weapons... it's also the ''weakest'' of all the summons, with a mere 8 damage and no ranged ability.
* MoralEventHorizon: The Player Character. In order to progress to the endgame, you must summon a boss in the Underworld, and in order to do so, you must murder the Guide with the Guide Voodoo Doll. As of 1.1, it's clear that death is not cheap for the non player character allies, as when they die they are not resurrected, but rather replaced, and thus this amounts to murdering the Guide simply to progress in the game.
** Unless of course, [[TheScrappy you hate the Guide]] which [[{{TakeThatScrappy}} leads to...]]
* NauseaFuel: [[EvilIsVisceral The Crimson]]. From the sound Blood Crawlers make when struck to the UncannyValley Face Monsters and the disturbing music, the biome is {{Squick}} embodied.
* PainfulRhyme: The enemy Ichor Sticker was clearly given its name because the developers thought it rhymed. It doesn't. Ichor is pronounced with a long I sound followed by an "oo" sound ("eye-kor"), and sounds nothing like the word "sticker."
** There's actually another pronunciation for Ichor, "ee-kor". Which still does not rhyme, but sounds a bit better.
* ParanoiaFuel: The underground is sprinkled with with hard-to-spot pressure plates that trigger dart traps, falling boulders, or even land mines.
** No matter what quarantine measures you take before activating Hardmode, and no matter how quickly you isolate the Corruption/Crimson and Hallow spread by defeating the Wall of Flesh, every time you smash a Demon/Crimson Altar there's a chance that some brick, somewhere, is converted to one of those contagious biomes. And you probably won't discover it until you go mining one day and discover another chunk of the map is now filled with horrors or fey monsters.
* PlayerPunch: Want to enable the game's Hard Mode and get access to a whole bunch of cool new stuff? You have to kill the Guide - the first NPC who joined you in your new world, and who spent the entire game up to that point freely sharing advice and crafting recipes with you. [[WhatTheHellPlayer You are a terrible person]]!
* PortingDisaster: In the Vita's case, suffered two major {{Game Breaking Bug}}s in its history. One, where after the 1.2 Update, corrupted all worlds that has the fireplace item. Two, which causes the vita to fail to save the game and cause a Crash to the Vita's menu. As of this writing, it's been unfixed for three months.
* PraisingShowsYouDontWatch: The game had a community like this pre-release, with many people praising the game well before it came out and claiming it to be nothing like ''VideoGame/{{Minecraft}}'', despite only a limited number of them having played it at that point.
* RescuedFromTheScrappyHeap: Surprisingly enough, the [[InfinityPlusOneSword Terra Blade]]. Even though it had extremely high power and {{Sword Beam}}s, many people considered it a letdown for the effort needed to create it and consider it inferior to the Death Sickle, Paladin's Hammer, Horseman's Blade and Vampire Knives due to its lack of auto-swing. Cue Version 1.2.4, it got the auto-swing it deserved, and it's now back as a contender for best melee weapon in the game.
* TheScrappy:
** The NPC known as "Guide" who appears in every world upon creation, runs around and will move into any house you build. He's supposed to give tips to new players, but [[StopHelpingMe there's no way to get rid of him]]; even if he dies, he respawns within a minute. But the worst of all is that he often [[TooDumbToLive opens your house's front doors during night when there's zombies outside]], so it makes them able to enter your house and kill you. Even the creators themselves find him incredibly annoying: they walled him in and trapped him in their LetsPlay (which doesn't help anyway because he can teleport). Redigit even added an item called the [[TakeThatScrappy Guide Voodoo Doll]], [[spoiler:[[VideogameCrueltyPunishment which summons The Wall of Flesh if thrown into the lava pits of the Underworld.]]]]
*** Since 1.0.5, he has become much more useful as he can show you everything you can craft with an item if you show it to him. Crafting is no longer a guessing game, and it certainly makes the world a whole lot kinder to new players who try to experience the game without immediately resorting to a wiki.
*** Lampshaded in the Steam card for him. "He thought it would be funny to open your door and let zombies in, you thought it would be fun to feed his soul to the lord of eternal nightmares."
** As of 1.2.4, The Guide's Scrappy-ness is quickly being eclipsed by The Angler, who is the only child character in the game...which is a title he tarnishes by being an utterly infuriating SpoiledBrat. He's bossy and demanding, he treats your character like dirt, and is constantly pulling "pranks" on the other residents, such as putting undead fish into their furniture and piranha teeth into chairs. And you can only do [[ScrappyMechanic one of his fishing quests per day]], which is especially aggravating when you're trying to get the rarer rewards which have an already infuriatingly low drop rate. Even worse for those who want to give him the same treatment as The Guide, InfantImmortality is in full effect, even lampshaded somewhat. If his HP is ever reduced to 0, [[NoSell he simply poofs away in a puff of smoke, with the chat log "<Name> Has left."]] This being in a game that contains voodoo magic, bloodthirsty organs, and hell itself.
* ScrappyMechanic:
** Potion Sickness: whenever you use any item that heals your health, you need to wait a minute before you can use another. While obviously tailored to prevent health potion abuse, 60 seconds is an eternity in boss time. There's an accessory that can reduce it to 45 seconds.
** Occasionally it will start to rain in the overworld, with each storm lasting about 24 minutes. This wouldn't be so bad if storms didn't darken the brightness a bit, cause flying fish to spawn (basically [[GoddamnedBats demon eyes]] that can appear during the day), and nullify the blooming conditions for Fireblossoms. Furthermore, they sometimes drag on if you're unlucky, with a storm coming up right after the previous one. On the plus side, you need it for Waterleaves to bloom and and it drastically increases fishing power. It's also the only time the Ice Golems will spawn in the snow biome on hardmode.
** Blood moons and Solar Eclipses, once you get enough good gear. While they are threatening, intense and fun early on, after a while, they basically become the event versions of GoddamnedBats.
** The Angler's fishing quests can only be done once per in-game day, which is infuriating because he possesses six unique items which he gives out randomly, three of which are necessary to craft the Cell Phone.
* ScrappyWeapon: Nobody uses short swords. Rather than swinging it overhead in an arc, your character thrusts it forward, making it almost useless against anything that doesn't walk right into it.
* {{Squick}}: The Wall of Flesh, a gigantic... wall of flesh, with flunkies in the form of tiny mouths hanging off of veins that try to attack you. It can ''puke leeches'' to attack you with.
** The Crimson is one big land of Squick. Blood drips from ''everything'', even the trees. The enemies there have names like "[[http://terraria.gamepedia.com/Blood_Crawler Blood Crawler]]" (a giant tick/spider), and [[http://terraria.gamepedia.com/Floaty_Gross "Floaty Gross"]] (a ghost that constantly drips...some sort of unpleasant fluid), and you can farm things like Flesh Blocks (to build flesh furniture, of course), Vertebrae, and Meat Grinders.
* SidetrackedByTheGoldSaucer: The [[http://terraria.gamepedia.com/Angler fishing minigame/sidequest]] is rather elaborate, with around 30 possible quest rewards requiring ''way'' more than 30 fishing trips to get them all because most are [[LuckBasedMission rare and random]]. Only one fishing quest is offered per in-game day, but they often eat up a lot of time and distract you from the usual exploring/fighting/building/boss-battling. Or you may realize that you often fish up crates, which sometimes contain [[SequenceBreaking high-level metals you aren't supposed to have yet...]]
* StopHelpingMe:
** The guide NPC who functions as a newbie hint guide. Unfortunately, he likes to path around the players and can enter their normally safe houses, bringing the monsters howling at the doors inside with him. [=NPCs=] running from monsters who have gotten into their homes can also run to your house and open the door that kept them out.
** The baby slime summoned from the rare Slime Staff. It has GameplayAllyImmortality and hits rather fast and can kill weaker enemies quickly. Unfortunately it can also negate your attacks due to the MercyInvincibility the mobs have while being pummeled by the slime, thus your attacks don't always register. During hardmode, it quickly becomes obsolete due to its low attack power, and the higher defense hardmode monsters have. By that point you'll probably be better off killing things on your own rather than rely on the slime.
** Some summons in general can end up being this, especially the fast attacking ones like the Stardust Dragon. They can constantly trigger enemies' and bosses' MercyInvincibility which will leave you no room to get any hits in for yourself, which in turn can drastically lower your damage.
* TakeThatScrappy: For players who hate the Guide for allowing nighttime enemies into their houses, it can be satisfying that the procedure to [[spoiler:summon the Wall of Flesh]] involves [[spoiler:destroying the Guide via a voodoo doll]] rather than a PlayerPunch.
* TearJerker: A painting found in the dungeon depicts the late Sparky Doo, once Redigit and Cenx's dog. " In loving memory."
* ThatOneAchievement:
** The "Knight in Shining Armors" achievement on the console version. To get it, you have to obtain the ultra-rare Mining Armor, craft every helmet for the Hardmode armors, get every other piece of armor, beat Ocram up to 30 times, then make 3 full sets of Hallowed Armor, plus 3 more of each Hardmode armor, and get a few hundred bars of Adamantite (the rarest ore in the game.)
** "Supreme Helper Minion" on the PC version. Better hope you have the patience of a saint, as this requires you to complete ''200'' angler fishing quests. And since [[ScrappyMechanic only one quest can be done per in-game day]], this will involve ''lots and lots'' of waiting. To put in perspective, you could theoretically do about 60 quests in a real-time day if you stayed up and were playing constantly. That means ''three'' real days of non-stop gameplay to complete 200 quests. Thankfully this achievement counts up alongside the other achievements related to quest fishing and the process can be slightly sped up with the Enchanted Sundial to skip to 4:30 AM (when a new day starts). Only problem is the Sundial has a cooldown of it's own that lasts a whole in-game week or 168 real minutes.
* ThatOneAttack: In Expert Mode, most bosses gain new attacks to make fighting them even more obnoxious.
** The Eye of Cthulhu, once it's down to half-health, gains a super-fast charge attack where it whips around the screen like a blur, and as it takes more damage it uses this attack more often. By the time it's on its last legs, it does it non-stop, making getting that last sliver off ten times more difficult.
** The Brain of Cthulhu is even worse, as its Creepers now inflict random status effects when they hit you, which can quickly and ridiculously stack up if you're caught in a group of them. This includes the Broken Armor debuff.
* ThatOneBoss: The majority of bosses in Terraria have the potential to be this.
** Skeletron Prime if you're trying to beat him solo. He has four arms, each of which 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, and if you don't beat him by then he becomes practically unbeatable and gets a OneHitKO attack.
** 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 BeamSpam from both eyes with increasing frequency as you do damage. On top of that, it accelerates as it takes damage; on its last legs, the Wall is actually faster than the player at full sprint. 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 [[InfinityPlusOneSword Terra Blade]]) for round 2 (or whatever number fight it is) all the more satisfying. Adding to this is the fact that he's prone to bugs. He may accidentally spawn heading the wrong way, which is pretty much instant death because any prepared player will summon him at the far end of the map. He can also spawn much further down than he'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 reason why the characters' page says there's no middle ground - you're either overprepared or dead.
** The Destroyer has become notorious as the most difficult of the three mech bosses, ever since it got buffed. It was briefly nerfed in 1.2 reducing its defence, 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!
** How about The Twins? Sure, they don't seem so bad at first, until you get them down to half health. Spazmatism starts shooting a stream of cursed flames and trying to eat you, while Retinazer steps up the EyeBeams to BeamSpam levels.
** Plantera suffers from a similar problem. She has a ton of HP, shoots petals (homing in Expert) and spiked balls that do a lot more damage, but if you prepared 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 causes even more damage. For added measure, Chlorophyte homing bullets will be negated by the CombatTentacles she spawns for the second half, which forces you into either melee 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--[[https://youtu.be/6AgX3jsrTQY She absolutely hates it.]]
** The Pumpkin Moon. It starts out simple, with [[TheGoomba Scarecrows]], [[MightyGlacier Splinterlings]], and [[LightningBruiser Hellhounds]] that can be fairly easily handled with good crowd control weapons. Then you hit wave 4 and the [[WhenTreesAttack Mourning Wood]] shows up. It's got 12,000 HP, it fires a huge spray of fire that sticks around on the ground for a few seconds and does huge damage, and it's surprisingly fast. It only gets worse from there.
** The Frost Moon. It's [[UpToEleven The Pumpkin Moon Taken to Eleven]] The first few enemies like [[TheGoomba Zombie Elves]] and Gingerbread men, can be handled with ease with Pumpkin Moon loot, then you hit Wave 4 and the Everscreams come out with 13000 HP, being a harder version of the Mourning Wood. Later, you have to fight [[BadSanta Santa-NK1]] Which fire very powerful missiles and presents, that has 18000 HP. Even later, from waves 12 onwards you fight the IceQueen with 34000 HP, which is pretty much Pumpking on crack, flying everywhere, firing ice shards. It gets hectic really fast, good luck getting past wave 12 on your own. To put it? Some people consider the Ice Queen to be ''tougher'' than Duke Fishron (see below).
** Duke Fishron introduced in 1.2.4 version. [[LightningBruiser He's extremely fast, powerful and has 50,000 HP to boot]], fighting him in a small-medium sized arena is downright suicidal as he will create huge tornadoes that not only shoot high-speed, high damaging sharks in a very fast rate, but will also limit the player's movements. Think it can't get any worse? It TurnsRed when low on HP becoming even faster, 1.5x as painful, and more erratic. In 1.3, he got buffed even further--he will get pissed and now ''repeatedly'' use his fast charging attack if he leaves the ocean. Yes, that includes flying too high into space, which means the "arena" you can fight him in is rather small!
** In Expert Mode, all the bosses become this, as they're twice as strong while you aren't. This is especially bad in the early game, as your options are limited because the bosses are holding the items you need to progress.
* ThatOneLevel:
** The Underground Jungle. It's a humongous cavern that stretches from below the Jungle to the Underworld. What's so hard about it? It's a nightmare to navigate, it's swarming with Hornets and Man Eaters (horrendous DemonicSpiders), and it's got several rare and rather useful items hidden in it. (Enable hardmode in 1.2 and its difficulty is boosted to BonusLevelOfHell.)
** The post-Plantera Dungeon, by and far. Originally it's dangerous but survivable and by the time you reach hardmode and have high end equipment it's basically a BreatherLevel. Then you defeat Plantera and the crap hits the fan. Suddenly the Dungeon is filled with extremely powerful skeletons that can soak damage like nothing, Necromancers that can bounce nigh-instantaneous shadow bolts around corners to hit you and teleport away whenever they take damage, Diabolists that shoot exploding, un-blockable fireballs through walls at you and also teleport on damage, Paladins that have more health than some bosses and rapidly throw hammers at your face for massive damage, Skeleton Snipers that can two-shot you from across a room. Basically every enemy in the post-Plantera Dungeon is either a DemonicSpider or a {{Goddamned Bat|s}} designed to distract you while the stronger enemies kill you. Even after you kill them you're still not safe because there's a chance every enemy you kill might spawn a Dungeon Spirit which charges you at high speed, straight through walls! The good news is that if you can survive this onslaught you can get some of the most powerful equipment in the game here.
* UglyCute: The Eater of Worlds and the Brain of Cthulhu have drops that allow you to get a pet baby Eater and baby Face Monster respectively. Despite being based off their NightmareFuel counterparts, their miniature size makes them look somewhat cute.
%% * WhatDoYouMeanItsForKids: 1.2 introduces the Crimson. In a T-rated game.
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