In Akkadian mythology the Rabisu ("the lurker"; Sumerian 𒉺𒁽 Maškim, "deputy, attorney"), or possibly Rabasa, are vampiric spirits, daimons, or demons. The Rabisu are associated in mythology with the Curse of Akkad. A consistent translation of "Rabisu" is "Lingerers". The Rabisu, whether intending malicious actions or not, linger around those who have been found wayward or to be rewarded by the deity Enlil.

The spirit identified by the Akkadians as "Rabisu" is not an inherently evil spirit. Despite the Hebrew Bible referring to demons as evil by nature, the demonology expressed by the Akkadians suggests that Rabisu, rather than being an entity of evil, was "a neutral being that is nothing other than a current of wind dispatched by the deities to perform certain duties". Rather, the Rabisu was a spirit sent out to correct the transgressions committed by humans.

When one refers to the spirit of the Rabisu as an evil entity (Evil Rabisu) it may be better interpreted as reference to malicious action performed by the Rabisu in response to the wayward actions of an afflicted human. That is, the malicious event does not reflect the Rabisu spirit as a whole.

The Sumerian and Akkadian deity Enlil, a major god of the earth and sky, is the sender of the "windy beings" known as Rabisu. The Rabisu, rather than acting as predatory demons with their own malicious will, were more like links between the divine beings of Heaven and the Earth. In mythology, Enlil sent the spirit of the Rabisu as a sort of messenger. Whether the message entailed good or bad things for the receiver was not a reflection upon the Rabisu but rather the consequence of human actions, which themselves were of different moral character.

The Rabisu, though believed to hold no moral implications, were often opposed by hero figures. In Sumerian texts, the hero is named Hendursanga, roughly translated as "Watchman of the Night." Other translations include "Isums" which is interpretated as "Herald of the Gods, Watchman of the Streets" (University of Chicago Press 3).^{[citation needed]}

The Rabisu is also listed in the rituals of Šurpu which have to do with burning, such as the symbolic burning of witches. The Šurpu ritual allows the banishment of Rabisu described as "a demon that springs unawares on its victims".

The Curse of Akkad, also known as The Curse of Agade, is a story told by Sumerians during the Third Dynasty of Ur (2047-1750BCE) about the Akkadian king Naram-Sin who was the grandson and successor of Sargon the Great. Sometimes the Curse is described as Naram-Sin's fight with Enlil. Naram-Sin had grown discontent with himself and blamed the gods for not providing relief from his sorrows. Naram-Sin took up arms against Enlil who, in turn, sent the Rabisu to correct Naram-Sin's transgressions. The story ends with the complete destruction of the city of Akkad, Enlil triumphing over the earthly human domain. This story can be read in the context of the Rabisu as the enforcers of divine will.

The story of the Curse of Akkad is similar to a myth of the "lost city" of Ubar, sometimes referred to as "Atlantis of the Sands", located farther to the south in southeastern Oman. The Rabisu were noted to operate as a flock or unit, as opposed to individual spirits. It was believed that Enlil would send "flocks" of Rabisu in the form of storms of wind, sometimes carrying dust or sand storms.