Utukku (Utukku Lemnu)

The utukku were a class of supernatural beings in Sumerian and Akkadian belief, ranging from the spirits of dead humans to predatory supernatural entities. They were catalogued in the massive 'Udug-hul' (Evil Demons) cuneiform series — twelve tablets of incantations against them. Some were malevolent by nature; others were spirits of those who died violent or premature deaths. They attacked the living through all the standard channels — night, threshold moments, illness.

No secure iconographic representation of the udug/utukku has been identified. Ritual and literary texts ascribe to them non-anatomical, often metaphorical features commonly shared with other Mesopotamian hostile spirits: a dark shadow, an absence of light surrounding them, associations with poison, and a deafening voice. These attributes function as descriptive markers in exorcistic discourse rather than precise physiological description.

The surviving Udug Hul exorcistic texts emphasize the role of the evil udug in causing disease and affliction; they are depicted as malicious and hostile toward humans. Textual tradition also shows variability within the broader demon class (for example later named figures like Pazuzu), indicating some named demons could be hostile to other spirits and to gods, but the Udug Hul corpus specifically frames udug/utukku primarily as causes of illness requiring ritual intervention by an exorcist.