Creepers are an aggressive kamikaze mob found in Minecraft. 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.
Killing a Creeper will not cause it to detonate, and Creepers who detonate do not drop items. Creepers commonly drop gunpowder, which is used in the making of TNT, and on the rare occurrence of a Creeper being killed by a Skeleton's arrow (an example of monster infighting), the Creeper may drop an LP record.
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.
As of 1.2.1, a Creeper will run away from ocelots and cats.