Human on Ghost
Notable Examples: Ghost (1990), Casper (1995), Haunted (1995), Scary Movie 2 (2001)
In 1990, Ghost accomplished what Warm Bodies would love to: It made audiences want to see a human get freaky with one of the undead. Did it help that the undead character was played by Patrick Swayze? Possibly. Did it help that sensual pottery was involved? Definitely.
Curiously, a number of films have made human and ghost coupling look fun, or has at least depicted the individuals involved as having enjoyed themselves. In Scary Movie 2, Tori Spelling's character enjoys her romp so much, she has a smoke with the spirit right after. Same goes for the British picture Haunted, where Aidan Quinn's character (alive) gets freaky with Kate Beckinsale's character (dead).
This is really fucking weird, right?