Mimics

A Mimic is an uncommon Hardmode enemy disguised as a Chest, appearing as the appropriate Chest type for the environment. Mimics will look exactly like Chests until approached or attacked, at which point they will chase the player.

Mimics take on the appearance of Chests that would normally be found in a given area: normal brown chests closer to the surface, gold chests found underground, and locked Shadow chests in The Underworld. Mimics that spawn in a Snow biome not only take the appearance of Ice Chests, but also have their own unique set of ice-themed drops.

Mimics can be spawned by the player using the Chest Statue &mdash; even prior to Hardmode &mdash; but these will not drop any coins or items besides the Mimic Banner.

Identifying
While disguised, Mimics will not show a usual enemy tooltip when hovering the mouse cursor over them, except in the mobile version. Below are some tips to help differentiate real chests from Mimics.
 * Real Chests will show up on the minimap, but Mimics will not.
 * The Spelunker Potion will not cause a Mimic to glow, but the Hunter Potion will.
 * Mimics disguised as Gold Chests or Shadow Chests will not emit a sparkle effect the way the real versions do.
 * Hitting an inactive Mimic with any weapon will activate it, even from afar.
 * Mimics may not line up properly with blocks, as normal Chests would. They can also appear atop empty tiles (eg. slopes), where real chests can never be placed.
 * Mimics can appear in front of background objects or other enemies, while real chests cannot.
 * Mimics cannot disguise themselves as unlocked Shadow Chests. Unlocked Shadow Chests are therefore always real chests.
 * The Scourge of the Corruptor's tiny Eaters will home in on disguised Mimics.
 * Empty and collect every chest you find, or mark real Chests with a torch or an uncommon block. If you see an unmarked chest in an underground area you've already visited, it's likely a Mimic.

Tips

 * Targeting Mimics may help players making their way through early Hardmode, and they drop high-damage weapons and good defensive accessories; as well as around, which can help with Hardmode's higher prices.
 * An easy way to kill Mimics early in Hardmode is to grapple a high place and attack with a ranged weapon.
 * With 3 or more players, Mimics will never stay in their disguised state.

Trivia

 * Mimics first appeared in Dungeons & Dragons in 1977, and have appeared in countless publications since.