In 1990, we had some brand new HP disks the size of a washing machine. Capacity 650MB.
Some software was written to move the head assembly from end to end. This would cause so much vibration the the whole machine would “walk” around.
The machine room had video cameras, and sometimes if you saw some maintenance people in the machine room, you would launch the “Butterfly test” on all the drives. They would come alive like a bad horror movie, and all walk around. The poor maintenance person would try to run out befor the exit got blocked. (Slashdot comment)