Sea Fright

When a treasure-seeker uncovers a treasure chest on the ocean floor, he unwittingly summons a ship of pirate ghosts, who wreack havoc on New York in order to reclaim their treasure. The ship, called The Stag, is commanded by Captain Jack Higgins, one of the most notorious pirates in history, whose pirates prove to be too much for the Ghostbusters to handle. Despite being outnumbered, the Ghostbusters give chase to the pirates in order to stop them. To make things worse, Slimer tries to help, and gets into a fight with a ghost parrot, while the guys take on Higgins and his pirates, ambushing The Stag first from another land-beached ship, and then leading the pirates into a trap so that they can end their plundering once and for all.