What makes a demon such a genius? It is not that she is so very smart. “Genius” is the term used for a hybrid being who is composed of animal parts. A popular one in Ancient Egypt combined the form of a hippopotamus, lioness (or other big wild feline), and crocodile. This form is used for a number of entities including Taweret (“the Great One”), Ipet, and Reret.
Taweret genius highlighted on Middle Kingdom magic ivory wand
The sketch showing a close-up from this magic ivory wand makes it clear. Note the feline head, hippo body, and crocodile on her back. This particular one acts as a protective demon, as show by the snakes coming out of her mouth and the butcher knives she holds.
Close-up sketch of Taweret showing genius hybrid features (courtesy of Felicitas Weber)
While that genius is generally helpful, the same form is used for Ammit, (the “Devourer” aka Ammut), a demon who was more feared. She waits to eat the heart of those who do not pass the weighing of the heart. Note how Ammit appears with the head of a crocodile, forepart of a lioness, and hippo butt. In this image from a prt m hrw (aka “Book of the Dead”) in the Louvre, she appears really relaxed!
Ammit waiting by a lake of fire