Ordinary Mimics look like chests until approached or attacked, at which point they come to life and chase the player by hopping towards them. Before revealing themselves, they take on the appearance of chests normally found in the biome they are encountered in: regular Chests above the Underground layer, Gold Chests Underground, and locked Shadow Chests in The Underworld.
Mimics that spawn in a Snow biome on ice or snow take on the appearance of Frozen / Ice Chests and also have their own unique set of ice-themed drops.
These Mimics are rarer, and much more powerful in every way, than the normal Mimics (they can be even more deadly than any pre-Hardmode boss, with the possible exception of the Wall of Flesh and Deerclops). They only spawn in the vicinity of the underground version of their corresponding biome.
Similar to ordinary Mimics, these special variants disguise themselves as "Chests" until approached or attacked, but they do not resemble any Chest type currently in the game, and are significantly larger than ordinary Chests.
Hallowed, Corrupt, and Crimson Mimics can also be summoned manually by the player, in Hardmode worlds only, by placing a Key of Light or a Key of Night inside an otherwise empty Chest; the Chest becomes a Mimic once it is closed. The natural evil biome of the current world determines whether a Corrupt or a Crimson Mimic is summoned via the Key of Night.
All four special Mimics have the same attack patterns:
The Mimic hops toward the player, much like a normal Mimic would. After three successive hops, the Mimic will perform one of the three moves below before repeating the pattern:
It performs three rapid dashes, during which it can also jump extremely high.
It periodically shuts itself and remains stationary, during which it becomes invincible to attacks. In Expert Mode, it will reflect projectiles fired at it, which can damage the player firing. It can reflect bullets, arrows, and darts, but not rockets, and the projectiles of numerous other weapons. For the complete list, see List of reflected projectiles.
It performs a "pound" attack, whereby it leaps into the air above the player and swiftly drops down (similar to Giant Tortoise attacks). During this attack, the Mimic can travel through blocks (unlike Giant Tortoises).
If the player attempts to escape, the Mimic dashes after the player at high speed (slightly over 51 mph). It can also travel through blocks when using this attack.
The Jungle Mimic has an additional "attack" called the "stuff cannon", which consists of hurling 10 of the following blocks (in "dropped form") at the player:
Spelunker Potion will not cause a Mimic to glow, but the Hunter Potion will. The Spelunker buff causes only normal chests to shine, while the Hunter buff colors all enemies red.
Mimics disguised as Gold Chests, Frozen Chests, or Shadow Chests will not produce their usual animated sparkle effect, as opposed to real chests. This does not work for Wooden Chests/Mimics.
This is especially apparent when there seem to be two chests nearby each other, which may rarely happen. If one of them is shining and the other one is not, the one that is not shining is a Mimic.
The Lifeform Analyzer will detect nearby Mimics. The Metal Detector can also give them away, as there will be no "Chest detected nearby!" message, provided there actually are no real chests nearby.
Mimics may not line up properly with blocks, as normal chests would. They can also spawn halfway inside blocks, partially hanging off a block over empty space, or in front of background objects and other enemies, where real chests cannot be placed.
Mimics cannot disguise themselves as unlocked Shadow Chests. Unlocked Shadow Chests are always real chests. Similarly, they cannot disguise themselves as locked Gold Chests, which appear in the Dungeon.
If a Mimic spawns in lava, it will take ticks of damage, even while it is not yet attacking the player.
Any Gold Chest found outside of Underground Cabins in maps generated between versions 126.96.36.199 and 188.8.131.52 is a Mimic. Between these two updates, Gold Chests did not naturally spawn outside of Underground Cabins anymore. However, on rare occasions, a Gold Chest may spawn below, beside, or above a Cabin due to structural generation errors.
A Mimic will always drop exactly one of the items from its loot table (excluding the Mimic Banner, and the potions for Biome Mimics).
Biome Mimics do not count towards and are unaffected by the Mimic Banner. They have no banners themselves.
Wooden Mimics will only spawn in front of natural walls on the surface.
The Corrupt and Crimson Mimics' drops encourage different play styles (not so for the dart weapons and hooks). This should be considered when selecting a biome evil when making a world.
The items from the Corrupt Mimic complement a distanced fighting technique: a strong knockback flail, a wall of flames to keep enemies away, and an item that decreases aggro range and increases damage to compensate for the low damage output of such technique.
The items from the Crimson Mimic complement an aggressive fighting technique: one of the smallest melee weapons in the game, a life-steal weapon to recover lost health, and an item that increases aggro range and grants defense to compensate for the high damage intake of such a technique.
Targeting Mimics can help players making their way through early Hardmode, as they drop high-damage weapons and good defensive accessories, as well as around 10 (25), which can help with Hardmode's higher prices.
Biome Mimics, despite being significantly tougher, drop less money than the normal variants (only 3 / 750). However, their item drops tend to be far more useful and valuable. Besides advanced weapons and tools, they drop Greater Healing Potions and Greater Mana Potions, which are handy in early Hardmode, before the player can craft their own.
Players should be careful when mining near the Underground Crimson/Corruption and Hallow biomes very early in Hardmode, lest a Biome Mimic spawns and catches the player unaware. Carrying a Lifeform Analyzer or one of its upgrades in the inventory can help warn the player.
Biome Mimics are very difficult to fight in a cramped area with limited mobility. Their attacks are very fast, allowing them to easily catch even players with early-Hardmode wings, and they can phase through tiles, meaning that players fighting them in close quarters in an area with limited space are at an extreme disadvantage, even well into Hardmode (especially in Expert or Master Mode). Players in early Hardmode should seriously consider only attempting to fight Biome Mimics in open areas such as larger caves with abundant room to maneuver.
Biome Mimics can easily be defeated in early Hardmode on flat ground and while riding a Basilisk Mount, helping the player gain extra speed to dodge attacks and having slanted horizontal blocks to the left or right going upwards. This gives the player some time to go to the other side and restore health or mana and it also helps while going back and forth to dodge the Mimic's jumps, invincible/deflecting state and pouncing.
Biome Mimics that are manually summoned can be easily defeated by using a platform very high in the air, such that the Mimics can barely reach the player. They will jump up constantly from the surface below (which will usually be slightly off-screen), in such a way that they are very easy to dodge with minimal movement. Note that they will be able to do a pounce and can potentially reach the platform.
Biome Mimics will travel through blocks in the duration of some of their attacks so simply grappling to a high spot will not work on them like it would on their less powerful relatives.
In Expert Mode, firing at a Biome Mimic with a high-damage, single-hit weapon such as the Sniper Rifle should be avoided. The reflected projectile from said weapon can easily kill the player if the Mimic is closed, especially when unprepared.
If fought in an open area, wings are useful for dodging the Biome Mimic's attacks. The Leaf Wings are a good set of wings obtainable in early Hardmode.
To spawn a Corrupt/Crimson Mimic in a world of the opposite evil, it is possible to buy seeds of the opposite evil from the Dryad while she is in a Graveyard in Hardmode. These can then either be used with grass to spread the evil, or it can be made into Thrown Water with which the player can make an artificial Underground Corrupt/Crimson biome.
Biome Mimics can easily be killed by lava, though remember to only use a small amount of lava to prevent burning the coins.
When Mimics were first introduced, it was possible for them to appear as a Skeleton instead. This was later fixed after an unknown update.
Lost Girls act similar to Mimics; they disguise and then reveal themselves to be Nymphs and try to kill the player.
Despite Mimics having a rarity of 4 on the Lifeform Analyzer, they are one of the more commonly found "rare" enemies, when compared to the other rarity 4 enemy, Tim.
Biome Mimics are the one of the three non-boss enemies which are manually spawnable (excluding enemies spawnable with using statues). The others are Wraiths which can be manually summoned by breaking an altar, and Ghosts which can be spawned by destroying Tombstones.
Despite their name, Biome Mimics do not actually resemble the Biome Chests found in the Dungeon. In fact, they do not completely resemble any actual Chest in the entire game.
Although not spawning through regular gameplay, Jungle Mimics are still detected by the Lifeform Analyzer.
Regular Mimics drop the most coins out of any non-boss enemy in the game, and even more than most pre-Hardmode bosses.
On the Desktop version, they have been overtaken by the Golden Slime. Despite this, the Mimic still drops the most coins out of any non-seed-specific enemy.
Biome Mimics each drop a melee, ranged, and magic weapon, as well as a grappling hook. In comparison to the Corrupt and Crimson Mimics, the Hallowed Mimic lacks an equipment item equivalent to the Putrid Scent or Flesh Knuckles.
There is no Bestiary entry for the Jungle Mimic, as it can only spawn in a Celebrationmk10 world and cannot be manually spawned.
3DS-Release: Introduced with Ice variant and accompanying drops.
↑ 1.01.1Information taken from the Desktop184.108.40.206 source code, method RegisterBoss_FrostMoon() in Terraria.GameContent.ItemDropRules.ItemDropDatabase.cs There may be inaccuracies, as the current Desktop version is 220.127.116.11.