The film's tagline is "Under the ocean, no one will hear your death" —a play on the famous Alien tagline.
In the episode itself, Marceline convinces Finn and Jake that her ghost friends can turn them into vampires so they can survive a trip to a "ghost dimension" to watch the movie. However, it turns out to be a played by Marceline and her ghost friends, who lead the duo through a series of "vampire" tests that are actually just dangerous stunts. [S2E26] Heat Signature
It is described as a thriller/horror film set underwater. The film's tagline is "Under the ocean, no