Element/sin :  female demon known as the Eater of the Dead and the Dweller in Amenta, the place where the sun sets.                 

Shape :  a monster with the hindquarters of a hippopotamus, forequarters of a lion, and head of a crocodile 

Myths :   Ammit waits in the Hall of Justice while the heart of the newly dead is weighed on the Great Balance against the feather of Maat. Thoth records the result. If the heart and the feather weigh exactly the same, and the beam of the Balance is horizontal, the soul is given "an abiding habitation in the Field of Offerings, as unto the Followers of Horus." If the heart proves to be "light in the scales," the soul of the become prey for Ammit. Any soul whose heart is devoured by this monster vanishs into oblivion.  

Source : The Book of the Dead