Ikiryō , also known as shōryō (しょうりょう), seirei (せいれい), or ikisudama (いきすだま), is a disembodied spirit or ghost in Japanese popular belief and fiction that leaves the body of a living person and subsequently haunts other people or places, sometimes across great distances. The term(s) are used in contrast to shiryō, which refers to the spirit of those who are already deceased.

In Japanese traditional beliefs and literature, onryō are a type of ghost believed to be capable of causing harm in the world of the living, injuring or killing enemies, or even causing natural disasters to exact vengeance to "redress" the wrongs it received while alive, then taking their spirits from their dying bodies. Onryō are often depicted as wronged women, who are traumatized, envied, disappointed, bitter, or just furious by what happened during life and exact revenge in death. These kinds of ghosts appear extremely vengeful, ruthless, heartless, brutal, cruel, deranged, egotistical, selfish, bloodthirsty, and cold-hearted.