Prank Idea #4 Bouncy Cushion

Do you remember the old bus seats where when somebody sat down beside you, you will be physically lifted up by the air trapped in the cushion. You will almost jump out of your seat if the guy next to you sat down very heavily!
Setup: Create a 2-seater bench that has an air-filled cushion such that anyone who sits on it will cause the other person sitting on it to bounce up.
Scene: The bench is setup up in some shopping centre where people can sit down.
Prank: This prank is really easy. Just place the bench and watch the chaos as unsuspecting people sit down on it. If the place is quiet, you could get an old male actor to wait for a lady to sit down first, and then go and sit down beside her really heavily. She should almost be bounced off the bench. If she stays seated, the old man will stand up (while being very oblivious), take out a handphone from him back pocket, and then sit down really heavily again. If she makes a movement to avoid being bounced off, the old man is to pretend to suddenly change his mind and remain standing. He keeps feigning to sit down and then watch the hilarity as the lady finally decides to give up sitting on the ridiculous bench.