"The Zombies" happen after a night of smoking marijuana. To have "the zombies one would feel groggy and slow (still high) for 1-5 hours after waking up. "Some zombies" is also an acceptable phrase.

A seemingly disposed fart, that you have to walk away from a group of people to disguise, and it creeps back up to you and your friends and one of them pukes.

A fart that someone smells and they make a "uuuuuuhhhggggg" screeching zombie noise.