The performer shows a wooden bottle and shows that it will not lie down on its side but keeps standing back up. That is because of the imp inside! The performer pulls out the imp between thumb and forefinger. 'Can you see it? I guess not. He's invisible!' Now the bottle will lay down on its side.
Great fun with a volunteer as part of a 'Do As I Do' routine. The bottle lays down for you, but when the volunteer tries to do the same, it just pops back up!