A particularly disturbing deviant of the standard orgasm in which one's face contorts so much that it no longer appears to belong to a living person.
This climax may be punctuated by the prototypical noises of the living dead. "Gwah!" and "hurgh!" are not uncommon, but the most-reported sounds are the characteristic moans of zombies in heat.
This definition is dedicated to all those who have lost their loved ones to (multiple) zombiegasms.
J&M are a couple.
J: Dreadful weather, isn't it?
M: Quite so. By the way, I'm about to come.
M: Gwaargh nuuugghh! uugh ghluhg mmmmmmmm...
J: M, a part of me died as soon as you started having that zombiegasm.
M: What's a zombiegasm?