Also, Ammit is a crocodile beast who, in Egyptian lore, represents "judgement" - Maat, the goddess of truth, weighs your heart against her feather and if your heart is too heavy, the crocodile eats it. I always see the crocodile as a symbol of whether or not the fool "makes the grade" and is able to ascend out of third density.
http://www.egyptian-scarabs.co.uk/weighi..._heart.htm
http://www.egyptian-scarabs.co.uk/weighi..._heart.htm