A delightfully dry humor courses through this three-part Halloween treat. First, Hop (a bunny) and Hip (a hippo) are deciding what they want to wear for costumes. Hop says he wants to be a pumpkin, but Hip says she wants to be one, too. Hop says he said it first and Hip will have to be something else. This throws Hip into a swivet, because all she really wants is to be a pumpkin. Hop finally bribes Hip with a promise of all the green M&Ms and a choice of costumes next year. Next, Hop is in a funk because it is raining on Halloween and no trick-or-treaters are coming. Hip tries to entice some by blowing a fan over the bowl of candy to send its aroma out into the street—no go—and playing scary music out the window—nope. Lastly, Hip decides she absolutely has to be a pumpkin, which angers Hop. Hip goes home and feels so bad that she lies on the floor, unable to bestir herself to go out. Hop materializes with a beautiful pumpkin suit for Hip, noting the differences between the two suits and, anyway, “I’m glad we’re trick-or-treating together.” Hip wants to know if she can have all the M&Ms, so as the green ones won’t be lonely. “Of course,” says Hop. The road of friendship is never simple, but it is always mysterious. Cartoony watercolors lend a smart animation to this tale of chums finding common ground. (Picture book. 3-6)