http://breezewiki.vernccvbvyi5qhfzyqengccj7lkove6bjot2xhh5kajhwvidqafczrad.onion/minecraft/wiki/Creeper
Creepers are bright green color to camouflage them for the original classic Minecraft foliage textures, which were bright shades of green, but has since been changed. 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...