Place a trigger operated flash strobe light behind the glass next to the bell. Now when the bell is pressed, there’s a loud “BANG!” and a blinding flash of light
Add a water balloon that drops from above and lands on the person at the same time
Make it so the front of the explosive pops forward, like on a piston. Their eyes will be focused on it when they press the button, having it jump towards them will be extra effective.
Even funnier if it makes a crazy loud « BANG » when attempting to ring it…
Pops up a Looney Tunes style flag reading Boom!
Place a trigger operated flash strobe light behind the glass next to the bell. Now when the bell is pressed, there’s a loud “BANG!” and a blinding flash of light
Add a water balloon that drops from above and lands on the person at the same time
Make it so the front of the explosive pops forward, like on a piston. Their eyes will be focused on it when they press the button, having it jump towards them will be extra effective.