Slumber Party Massacre III (1990)

As twilight descends after a sun-drenched volleyball game, a teenager, left to her own devices with her parents away, invites her closest friends for a seemingly innocent slumber party. The anticipated arrival of their boyfriends, hoping to inject playful terror into the evening, is soon overshadowed by a more ominous presence. An enigmatic stranger, first noticed lingering near the beach, is now observed circling the house. The carefree atmosphere dissolves as the group finds themselves facing a disquieting and inexplicable disappearance. Their night takes a sinister turn, and survival becomes the only game.