The ship is made to transport baby teeth to a place called Tooth Island. When its horns blow, dollars pop out.
Role in series
The Tooth Ferry is mentioned many times throughout the episode. It doesn't fully appear until the very end where SpongeBob shows Patrick and Squidward the Tooth Ferry. Squidward believed that the Tooth Ferry was a magical fairy instead of the actual boat.
"Tooth Ferry" is a pun on the fantasy figure "Tooth Fairy" and the type of ship called a ferry.