Minecraft wiki entry for Creating_a_challenge_map, associated text: Also, you might want to drop the player into a pit full of creepers. One of the nice things about this is the pit gets bigger as the creepers blow up. Give them a cheap tool such as an iron pickaxe, to kill the creepers with, and add some small elevations or safe spots, or a complex redstone device that can make them invisible. You could also add a disabled "creeper generator" that adds in creepers, and the player has to break it to stay alive.