John screwed a bolt in and finished the last adjustments on his most powerful and bizarre creation yet. His Defictionalizer laser! In the form of a small gun, anyone hit by this weapon would instantly believe they are an actor in their own life! Usually the actor or actress "portraying" the character has a drastically different personality to contrast with their role of course. As they change mentally and physically, nothing under the sun short of divine intervention can convince the newly minted 'actor' they were anything but who they are now.
As a secondary effect however, they will tend to be very committed to their role, almost to the point of obsession. At this, they'll occasionally show frustration and slipups when trying to get in character.
John flipped off the safety on the gun and went downstairs. He was in for a world of fun ahead of him.