In the early Q*Bert arcade games, there was some kind of mechanical device inside the game housing. If you were unlucky and maneuvered Q*Bert off of the pyramid, there would be this audible "SMACK" that you could feel through the joystick, presumably Q*Bert splatting on the floor of the housing. Quite a shock the first couple times it happened, or if you had been playing well for a long time. Sort of a precursor to the Rumble Pack stuff.

I seem to remember that this feature was not present in all the games, perhaps it was too expensive to implement or the mechanism broke a lot.