Silverfish (minecraft)

Silverfish are small, bug-like mobs which have silver skin and black eyes that hide in special blocks found in strongholds. These blocks look identical to stone bricks, cobblestone, or regular stone but take slightly more time to mine than normal with a pickaxe, and will take noticeably less time to mine without one. When the block is mined, the Silverfish will pop out and attack. Destroying the blocks via Creepers or TNT simply kills the silverfish. In regular gameplay, Silverfish blocks occur rarely. If left alone, silverfish can re-enter some blocks, namely cobblestone, regular stone, and stone bricks.