Redstone Bug

A Redstone Bug is a small hostile mob added in the 2.0 (purple) update. It is sometime created on top of Redstone when it activates. It is colored different shades of red depending on what power the Redstone that it spawned on top of had. It can also despawn and turn any kind of stone block into a Monster Egg, although if the Monster Egg is mined, the Redstone Bug will not respawn and a Silverfish is spawned instead. It was removed in the next update.