There are at least three films in the Heat Signature franchise mentioned in the episode. Episode Plot Context
The film's tagline is "Under the ocean, no one will hear your death" —a play on the famous Alien tagline. [S2E26] Heat Signature
Within the show's universe, Heat Signature is a pre-war film series that Finn and Jake consider a must-watch. Key details include: There are at least three films in the
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. Key details include: In the episode itself, Marceline
It is described as a thriller/horror film set underwater.