Minecraft wiki entry for Thunderstorm_survival, associated text: Skeleton traps look like bone/skeletal horses when created, but as soon as the player comes within ten blocks, the horse transforms into a skeleton horseman, and three more spawn instantly near it. They have the AI of a skeleton or skeleton jockey and the speed and agility of a horse. What's more, they don't despawn, and they don't burn if the sun comes out again, because they wear enchanted iron helmets. Their bows are enchanted as well.