Mr. Clam was a giant clam who lived in the deepest part of the ocean, near the sunken pirate ship Lucky Lady. when Dr. Ricer's Ultrasub was stolen by Apparitia and Long John Scarechrome, Ricer's young daughter Amanda managed to stowaway inside the sub in an attempt to stop them. The two ghosts both stepped out to face the Ghostbusters and retrieve the object of their search, a missing decoder box. This gave Amanda a chance to take the vehicle's controls and asked friendly Mr. Clam if she could use it's inside as a hidingplace.