At a loss for a show-and-tell topic, Patti invents a pet gorilla, named Bob for her favorite uncle; but when her gullible classmates believe her story, she has the new challenge of explaining the truth. Patti's problem is complicated when the class goes for a nature walk and her friends spy what looks like a gorilla through her bedroom window. Patti herself is perturbed by this unexplained apparition; but when she goes home, she discovers that the fuzzy brown bathrobe Grandma made, suspended from a bedpost, has moved in the wind to create the gorilla effect. Taking the robe to school to explain isn't easy, but Patti feels better when she's done it and is forgiven her fabrication. There's hardly enough in these mild events to make a six-chapter book, but Patti's learning experience is acceptable as an additional here-and-now story written in an easily comprehensible, though uninspired, style.