The Ghost in the Invisible Bikini (1966)

Hiram Stokley is a recently deceased corpse who learns that he has 24 hours to mastermind and perform one good deed in order to get into Heaven, so he enlists the help of his long deceased girlfriend Cecily, a ghost, to stop his greedy lawyer, Reginald Ripper and his henchman J. Sinister Hulk from claiming his estate for themselves and protecting his eligible heirs, Chuck, Lili, Hiram's cousin Myrtle, and her son who brings his beach party friends up at the mansion for a pool party while Reginald Ripper also employs his daughter Sinistra, and J. Sinister Hulk's slow-witted associates Chicken Feather and Yolanda to help them terrorize the teens, while dopey biker Eric Von Zipper and his Malibu Rat Pack bikers also get involved in pursuing Yolanda for a share of the estate.