We built one of those for a buddy's bachelor party. Handcuffs, chain, an eye bolt, a bowling ball, and a lot of adhesive.
It was entertaining. After we were all good and drunk and the party was winding down, we took turns smashing the bowling ball on the sidewalk, trying to bust it open. It was fun at the time, but looking back on it, I should probalby be glad that no one caught a bowling ball in the teeth.