I remember years back when some cameras used a "magic cube" flash. If you put one of the cubes in your pocket with keys, it could set off all four flash bulbs. I,m sure that caused some interesting motions.

And yes, nicads get hot when shorted. I plugged in an RX battery backwards once and unsoldered the pins in the receiver. Also ruined the battery and set off the basement smoke alarm, not the best move at 5am.