Crumble Undead is a magiccombatspell that becomes available at level 39. Crumble undead does extra damage to undead monsters, such as skeletons, ghosts, and zombies. Crumble undead costs 2 Earth-Runes, 2 Air-Runes, and 1 Chaos-Rune. and gives 98 Magic experience when casted. Crumble Undead can only be casted on undead creatures, and is strength 8. If the player attempts to cast it on living creatures it says "This spell can only be used on skeletons, zombies and ghosts".