Minecraft wiki entry for Creeper, associated text: Besides Steve and the removed human mob, the creeper is the oldest mob in Minecraft.
Notch stated on Twitter that "I imagine creepers as being made out of leaves or similar. I'm not sure why they explode.".[9]
When asked to describe the physical texture of a creeper, Notch said they would feel "crunchy, like dry leaves.".[10]
Creepers are their bright green color because Notch tried to make them well camouflaged for the original classic Minecraft foliage textures, which were bright shades of green.
In multiplayer, if a creeper is attacked by another player, and the other player runs out of sight, it does not attack any other players.
When asked how creepers trigger their explosive nature, Dinnerbone said "They're so nervous that they shake a lot, and then this sets them off the same way as how rubbing two sticks makes fire".[11]
If a charged creeper is given Invisibility, the "aura" effect is still visible.
A charged creeper explosion can inflict the greatest amount of damage any mob in the game can do at one time.
The creeper hiss sound uses the same sound file as when a block of TNT is primed, but played at a lower pitch.