In Sumerian mythology, what creature is the storm bird Anzu?

In Sumerian mythology, Anzu is a giant divine bird.

Anzu is a powerful birdlike creature associated with storms and the sky. In Akkadian sources, the name is often written Anzû, while the related Sumerian tradition uses the name Imdugud. Artistic representations commonly show a large bird with a lionlike head or features, although exact details vary by period and text.

The best-known story is the Anzu myth, in which the creature steals the Tablet of Destinies from the god Enlil. Possessing the tablet gives Anzu extraordinary authority, and the gods send a champion to recover it.

Anzu is sometimes labeled simply a thunderbird, but that modern comparison can obscure its Mesopotamian identity. It is also distinct from the lamassu, a protective hybrid figure usually shown with a human head, wings, and a bull or lion body.