Urdimmu, “Mad/raging Lion,” Sumerian UR.IDIM and giš.pirig.gal = ur-gu-lu-ú = ur-idim-[mu] in the lexical series ḪAR.gud = imrû = ballu, was an ancient Mesopotamian mythical creature in the form of a human headed lion-man who first appears during the Kassite period. He is pictured standing upright, wearing a horned tiara and holding a staff with an uskaru, or lunar crescent, at the tip. The lexical series ḪAR-ra=ḫubullu describes him as a kalbu šegû, “rabid dog,” but due to the propensity for Sumerian culture to group canines and felines together (ur.maḫ, big dog = lion) and Akkadian to separate them (nēšu, labbu = lion), the issue remains unresolved.
His appearance was essentially the opposite, or complement of that of Ugallu, with a human head replacing that of a lion and a lion’s body replacing that of a human. He appears in later iconography paired with Kusarikku, “Bull-Man,” a similar anthropomorphic character, as attendants to the god Šamaš. He is carved as a guardian figure on a doorway in Aššur-bāni-apli’s north palace at Nineveh. He appears as an intercessor with Marduk and Zarpanītu for the sick in rituals. He was especially revered in the Eanna in Uruk during the neo-Babylonian period where he seems to have taken on a cultic role, where the latest attestation was in the 29th year of Darius I. He became identified as MUL- or dUR.IDIM with the constellation known by the Greeks as Wolf (Lupus).