Mimic

Mimics are a type of enemy that look like wooden, golden or locked shadow chests. They will stay still initially, but will reveal themselves by jumping and biting the player if he/she moves within their attack range. Another way to reveal a Mimic is to shoot it from a distance. If the chest is a Mimic, it will take damage and move to attack the player, revealing itself in doing so.

Unlike regular chests, Mimics will not glow while under the effects of a Spelunker Potion, making it easy to differentiate between a Mimic and a standard chest. They do, however, glow under the effects of the Hunter Potion. Similar to their passive counterparts, Mimics can be found as close to the Surface as the dirt layer.

The Mimic is a hardmode monster, so it cannot be encountered naturally before the Wall of Flesh is defeated. Mimics can be spawned by powering the Chest Statue, but they will not drop any loot when created this way.

Trivia

 * Monsters that trick the players by disguising themselves as treasure chests are common place in many RPGs, mainly dungeon crawlers where treasure chests are common enough to make the player unsuspecting.
 * It acts alot like the mimics from dark souls, waiting for you to open it and then attacking.