The Ghost in the Invisible Bikini (1966)
The Ghost in the Invisible Bikini is the seventh (and last) of the American International Pictures (AIP) beach party films and was released in 1966. The entire film takes place in and around a haunted house with no beach in sight, with the teenage gang instead cavorting in and around it and the adjacent swimming pool. Besides the usual bikini-clad cast, random singing, silly plot line, musical guests, and ridiculous chases and fight scenes, the continuity linking this to the other beach films is the Rat Pack motorcycle gang led by Eric Von Zipper (Harvey Lembeck), as well as the appearance of previous beach party alumni Tommy Kirk, Deborah Walley, Bobbi Shaw, Jesse White, Aron Kincaid and Boris Karloff.
More at Wikipedia.