Victor the Happy Ghost

Peter, Ray, Egon, and Winston decide that a particular ghost is too cute to capture, so they take him under their wing. Once at home, the ghost, whom they name Victor, begins pulling pranks, which everyone pins on Slimer. Then, Slimer discovers that Victor is in fact another malevolent spirit. Noticing that Slimer is onto him, the now menacing Victor ensnares Slimer in the Ghostbusters' trap. It's only when the Ghostbusters take Victor on a case that they discover his true identity.