In nursery rhymes, oni are fearsome bogeymen that haunt the nightmares of children and adults alike, yet they are very real and always hungry. They find human babies especially delicious. Oni look like demonic ogres with blue or green skin, dark hair, and a pair of short ivory horns protruding from their foreheads. Their eyes are dark with strikingly white pupils, and their teeth and claws are jet black. Night Haunters. By the light of day, an oni hides its true form with magic, gaining the trust of those it intends to betray when darkness descends. These creatures can change their size as well as their shape, appearing as humanoids as they pass through towns, pretending to be travelers, woodcutters, or frontier folk. In such a form, an oni takes stock of the selection of humanoids in a settlement and devises ways to abduct and devour some of them. Magical Ogres. Oni are sometimes called ogre mages because of their innate magical ability. Though they are only distantly related to true ogres, they share the ogres' habit of joining forces with other evil creatures. An oni serves a master if doing so proves lucrative or provides it with a luxurious, well-defended home. Oni covet magic, and they work for evil wizards and hags in exchange for useful magic items.