The Crocodile was, as you might expect, a large crocodile. It wore a grey bonnet, a long white apron, and had a pair of small spectacles perched upon its snout.
After naughty children Tristram and Candy told lies to get their old nanny Mrs. Mac fired, they did the same thing to the first two nannies sent by the Animal MacMagic agency, a snake and a spider. However, the Crocodile was the third nanny that the agency sent, and it taught the pair a lesson they would never forget by swallowing them whole before laying them as eggs and hiding them in the cupboard.
Afterwards, Tristram and Candy became the most well-mannered children anybody could hope to meet.