The film's tagline is "Under the ocean, no one will hear your death" —a play on the famous Alien tagline.
You can find more details about this episode and others in the Adventure Time Viewing Guide or explore more lore on the Adventure Time Fandom Wiki . Sygnatura cieplna (film) | Pora na Przygodę! Wiki | Fandom
It is described as a thriller/horror film set underwater.
In the context of the episode " Heat Signature " (Season 2, Episode 26) , the "feature" refers to the fictional movie of the same name that Finn and Jake are trying to watch. About the Movie "Heat Signature"
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.
Within the show's universe, Heat Signature is a pre-war film series that Finn and Jake consider a must-watch. Key details include: