Dewey The Worm is a character at the beginning and ending of Shark Tale. The Iconic DreamWorks moon boy is fishing with his fishing rod when the worm happens to be at the end of the hook.
The moon boy throws his rod into the ocean (slinging the worm into the water). When he is in the water, he starts seeing shadows in the water.
He doesn't understand properly and thinks his brain is turned off. One of the shadows comes closer which scares the hell out of Dewey and it happens to be Lenny who then frees Dewey from the hook which makes life easier for Dewey.