Actually a rare form of ghoul; an undead troll is a troll victim of ghoul attack that arises after death as an undead monster that can only be "slain" by fire or acid. Undead trolls do hate sunlight which causes them great pain and suffering without killing them. A single monster has been known to devour a whole village in the course of an evening. Reasonably intact victims of an undead troll will arise after death as ghouls. Instinct: Devour the living!