One day, Hippo acts very strange. He bellows, spins in circles, and crashes into a tree. All of his friends think he has gone bananas! But has he? Or does he just have a bad toothache? Kevin O'Malley's bright marker and colored-pencil illustrations bring to life the animals of the Serengeti as Cuckoo Bird, Monkey, Leopard, Giraffe, Zebra, and Elephant try to figure out how to help their distraught friend. Their off-the-cuff solution brings this cheerful picture book to a humorous conclusion.