Rex receives a party invitation, but because he is feeling cross, he tears it up and stamps on it. He splashes little sister in a puddle too, and when he gets home he feels just like an angry bear. So he rolls himself in his furry rug and goes to sleep. In his dreams, he is going to strange parties, during which his clothes turn out to be tatty and too small, and he is always chased from these parties because of them. When mum finds him and pops him into the bath, she realises that his school clothes are, indeed, too small and rather worn. One suspects that his original anger over the invitation had to do with the state of his clothes. Weirdly reminiscent of Where the wild things are but original in its own right too. Beautifully written and illustrated.