If you put your spoon in the sun while you're in prison, a mouth will appear to scold you. You can never see who the mouth belongs to, but considering you're in prison it's probably a guard. Either way, that person doesn't like what you're doing and they keep scolding you when you put your spoon out into the sun.
One day you finally get fed up. You need to know who the mouth of the person who's scolding you is. You stick your spoon out into the sun and the mouth appears, scolding you right on time. You reach out and grab them. But in your hand is a pile of cats (かつ).