Get him a Pacman Frog - when they grow up, you feed them puppies.
Anyone have them as pets? How hard are they to keep? I've had the little aquatic ones that go in a fish tank before but we're redoing Thing Two's bedroom in frogs and I was thinking about getting him a little tree frog or something.
We had a Red Eyed Tree Frog, she "escaped", the lid wasn't on tight enough. You must make a vivarium for them to live comfortably. Complete with waterfall and plants, she lived a great life.
Fire belly toads are eaiser to take care of and pacman frogs bite. There are of course the african aquatic frogs that are fun but live in water.
Tree frogs are cool but definitely look into proper housing for them. Good Luck.