Creepers are exploding enemies from the game Minecraft, named for their habit of remaining perfectly silent until ready to explode, at which point they emit a sharp hissing sound that is feared by all players.
The Creeper design is based on a failed attempt to make a pig model, hence the four legs. Creepers make no idle noise and you will only hear them while they prepare to explode. Therefore you will only know if one is nearby if you see it first. Upon getting close enough, it will let out a loud hiss reminiscent of a burning fuse, and detonate after 1.5 seconds. If the player moves out of the Creeper's blast radius, the Creeper will cancel its detonation, run up to the player, and start again. This can be useful by smacking the creeper, moving back so it follows you, smacking it again, and so on until it is defeated. The player can also get close enough to a Creeper from above to hit it with a melee weapon without the Creeper's detonation being activated.
Creeper explosions will cause a 4x4x4 "spherical" crater from the point of detonation. Like TNT, if a Creeper explodes while partially or fully submerged in water, no damage is caused to the surrounding landscape, but the explosion will still cause damage to players and other mobs. Like all hostile mobs, Creepers only spawn in darkness, but unlike other hostile mobs, Creeper behaviour is totally unchanged in the light, and they do not catch fire in direct sunlight.
As of Beta 1.5, a Creeper can also be hit by lightning and become supercharged. In this state the Creeper is surrounded by a lightning aura, and will make a larger explosion and deal more damage.