Trampoline

A pig finds a trampoline with a warning sign that says not to use. Regardless, he jumps for a while, but the trampoline won't move. Furious, he stops trying to jump, but then he notices his weight is stretching the trampoline downward, and then he is flung to the ceiling where he is stuck along with other pigs. Another pig arrives, breaks the fourth wall, and it happens again.