What's Wrong with this picture?

What's wrong with this picture? Henry has been obsessed lately with throwing away his own garbage (a big plus for me). He also likes to take his cup to the sink when he's done. I do, however, have to keep track of what I've given him to eat and drink so that I don't find any nasty surprises later on. When I asked him where he put his banana peel, he said that he was feeding his horse...yeah...gross.