The paranoia beast is a many-headed, many-horned, invisible beast that descends upon a group of stoners as they slide into mashedness and causes them all to suspect each other of pretty much anything. Repeated exposure to the paranoia beast causes long-term psychosis, and can lead to complete insanity, during which the victim is unable to trust anyone or anything, and is permanently haunted by the beast night and day, when every creak, every knock, every minute sound is the beast's footsteps.
Stoner 1: Is Kenny okay? He's got that strange look in his eyes....
Stoner 2: Looks like he's being visited by the Paranoia Beast. Give him a bit, he'll come round.