Creeper

Creepers are Hostile Mobs that were added in Update 0.4.0. They spawn in light levels of 7 or below. They pose a significant threat to unsuspecting new Players, due to their dangerous ability to explode.

Offense
Creepers follow the Player when they are within 16 Blocks, and attack by exploding. When within three blocks of a player, Creepers will explode violently after 1.5 seconds. They make a sharp hissing sound and start blinking green and white before doing so. A Creeper's detonation can be halted if the Player gets out of its blast radius of 7 blocks.

Charged Creepers
Charged Creepers are a type of Creepers that were added in Update 0.12.1. They only spawn when Lightning strikes within a 5 block radius of a Creeper; however, this is very rare. They have a much larger explosion, and deal much more damage to the Player and the terrain. When they explode near a Zombie, Skeleton, Wither Skeleton, or another Creeper, this will cause the Mob to drop its head.

COMBAT
It is best to use a Bow when fighting Creepers; however, a strong Sword, like an Iron or Diamond Sword, can also be used as both will kill one in three hits. Another possible method is to force the Creeper to explode by igniting it with Flint and Steel, then running away, but this way can damage the terrain and prevent the Creeper from dropping its loot. Wolves are not recommended while fighting Creepers since their explosions can easily kill the Wolves. The best way to kill them is to run toward them and hit them, then run back and repeat until the creeper is dead.

Trivia

 * Creepers were accidentally created when Notch was programming the Pig, getting the height and length mixed up.
 * If Creepers explode on any kind of Slab, only the Slab will be destroyed.
 * Creeper Explosions cannot break Blocks in Water.
 * It will still harm the Player and any Mobs nearby.
 * Ocelots and Cats will scare Creepers away.
 * After Update 0.14.0, Creeper Explosions deal more damage to the Player, Creepers are slightly smaller (1.7 blocks tall rather than 1.8), and wearing a Creeper Head will knock their detection range of the wearer by 50%.
 * A flaming Creeper will catch the Player on Fire if it explodes.
 * As of Update 0.16.0, Creepers have idling sounds.
 * If the Player eats a Golden Apple, it may reduce the damage inflicted by the Creeper through its explosion.
 * If the Player gives a Charged Creeper a Potion of Invisibillity, the electric part will still be visible.