monkey trap

Have u ever heard of a monkey trap? I guess u could also call it a broderick trap. U put a treat or toy into a small jar, the "monkey" puts his hand in, makes a fist around the object and can't get his hand out. He will crawl around half the day with this jar on his hand. If u help him out, he will put the toy and then hand back in the jar all over again. Crazy monkey.