A fake chest that attacks players trying to take it's contents. You can tell the difference between a mimic from a regular chest by the small red square on the right side of the lock. These most likely represent their tongue. These spawn most frequently in the Dungeon Biome.
Mimics are an enemy first found in the role-playing game Dungeons and Dragons, and have appeared in countless publications since. Similarly to Magicite, the mimics in Dungeons and Dragons attack adventurers who are eager for loot.