Mimic

Mimic is a disguised ambush vermin that copies the block under its feet. At rest it passes for world terrain.

The disguise ends when it is hit or when a player brushes it closely enough and the awaken roll succeeds. After that it grows legs, chases like a living trap, and attacks at close range. About 10% spawn in a faster variant, which is why some Mimics feel much more violent than others.

Its copied block matters. The disguise decides whether pickaxes or axes are the right weakness, and the death table can include the copied block or the block's own loot on top of the usual tungsten appendages and ball essence.

Mimics appear across many ordinary biomes. If a lone block looks out of place, assume it might not stay a block.