It’s where someone you previously dated (and very likely cared for) or were even in a relationship with, ghosted you, only to then resurface some time later, most likely in the form of some sort of social media interaction or an out of the blue text message. Usually the zombieing happens just when you’ve gotten over the hurt of having them ghost you in the first place. Then, all of a sudden, they subtly reappear (I say subtle – it can feel like a slap in the face!) causing more emotional upset.
The act of unconsciously coiting (See: Coited) another human after a night of heavy drinking or other mind-altering substance ingestion in which both participants took part, yet neither participant remembers the actual sexual encounter. Mostly evident the morning after. Main side effects include a walk of shame and short term depression.
Barb: Ugh, I can't believe I had zombielingus with Sam last night.
Tom: Well, if in hindsight you knew that conscious you would have consented, there should be no shame.
Barb: That's deep.