THE GHOST IN THE INVISIBLE BIKINI (1966)

What the fark?  Boris Karloff dies and his spirit is woken up by the ghost of his ex-girlfriend who's been dead for 32 years.  He doesn't think it strange as she tells him that if he does a good deed within the next 24 hours he'll be allowed into Heaven and his ghost made young again...in order to have sex with with her in Heaven, I guess.  Anyway, he decides his good deed will be to save his heirs from his evil, murderous lawyer.  Why the fuck would you have a lawyer who's also a serial killer?!!!!!!!!?

So the heirs (and 50 of their closest pool partying friends) show up at this creepy-looking mansion for the will reading at midnight.  To pass the time until midnight they sing, swim in the pool, flirt and dance.  During all this, the evil lawyer has enlisted the help of some killers to try and murder the heirs in all kinds of horrible ways like axes, a hammer and even cutting in half on a giant saw!  There's also a random gang of biker idiots who are easily the funniest part of the movie.  When the leader, Eric Von Zipper, fell through that secret door I laughed for like 5 minutes straight.  I literally had to pause the movie I was laughing so hard.

For what it is...and I don't even know what it is, THE GHOST IN THE INVISIBLE BIKINI is funny in a stupid live action "Scooby-Doo" kind of way.  I imagine that 99.69% of the population would dislike this movie, but for whatever reason I was cracking up the entire movie.

Update: Well, I'm an idiot.  I just figured out that this is one of the original "Beach Party" movies.  It was suppose to star Frankie Avalon and Annette Funicello, but they passed and starred in FIREBALL 500 instead.

Part 1 - Beach Party (1963)
Part 2 - Muscle Beach Party (1964)
Part 3 - Bikini Beach (1964)
Part 4 - Pajama Party (1964)
Part 5 - Beach Blanket Bingo (1965)
Part 6 - How to Stuff a Wild Bikini (1965)
Part 8 - Back to the Beach (1987)

It's the nosy neighbor from ROSEMARY'S BABY.

 Is that one dude making the jacking off hand motion?!