From the info cards (also museum website):
"The strange vignette of a pregnant hippopotamus with a lion's mane, similar to the goddess Taweret, with a crocodile on her back and another nipping her paw is often found in Egyptian astronomical texts in connection with the northern constellations. However, the inscription at the left on this relief makes such a setting uncertain because it mentions Hapi, the god of the Nile's inundation. The textual genre and the provenance (temple or tomb wall or part of a sarcophagus?) thus remain unknown. The relief comes from either an unparalleled astronomical scene or a tableau featuring Hapi in which the representation of the hippo was "'borrowed" from astronomical scenes. If the hippo is Taweret, then the connection with Hapi is understandable because both had strong denotations of fertility."

"Ancient Egyptian women wore amulets of birth gods to protect them during and immediately after childbirth. One of these birth gods, a female deity often known as Taweret, was shown with the head and body of a hippopotamus, lion's paws, and a stylized crocodile hanging down her back. Her male counterpart, commonly called Bes, usually appeared frontally. In early Dynasty 18, artists depicted Bes with a human face and a lion's body and mane."

Bes was said to be her consort, but Taweret was also called the concubine of Set, as Set has been associated with the hippotamus. (Source Wilkinson, _Complete Gods..._)

Amulet of Taweret
Faience, 1 1/4 x 5/8 x 1/8 in. (3.2 x 1.6 x 0.3 cm)
New Kingdom, XVIII Dynasty, ca. 1539-1478 B.C.E.
Provenance not known
37.967E, Charles Edwin Wilbour Fund