The Mimic is a potentially hostile mob added by Project Zulu. They notably spawn inside of pyramids and labyrinths.
Mimics look like chests, and will remain passive until a player attempts to use them like a regular chest, gets too close, or attacks them.
Mimics can be easily avoided because placing the crosshair on one brings up its information in the HUD, alerting the player to its true nature.
Do you need a wiki for your Minecraft mod/gaming wiki? We'll host it for free! Contact us.