One night, a UFO lands in an ordinary backyard, and three green-spotted, dog-like aliens--Dalmartians--climb out and begin "collecting, bagging, and tagging specimens." When a boy named Stephen spots them, two of the Dalmartians flee, leaving one behind. Stephen is a gracious host and invites the alien into his house, but, despite similar looks to its terrestrial kin, this dog refuses to eat regular kibble or wear a leash. Compromise leads them on a two-legged walk to the park, where the alien dog is horrified by the prodding noses and shameless potty behaviors of the Earth pups. The alien canine nonetheless bonds with Stephen, and by the time otherworldly rescue comes, Stephen has made room for the peculiarities that come paw-in-paw with an alien dog. The art is as charming and quirky as the premise--the characters are drawn in minimalist charcoal strokes with much of their emotion conveyed through body language, and the alien's neon-green coloring pops on every page to remind viewers of its out-of-this-world origin. Details in the background, like a cat looking on horrified at a "dog" walking on two legs or the alien running water in the bathroom for extra privacy, add to the silliness. The emphasis on compromise between Stephen and his guest effectively applies to both friendship and pet ownership, with Stephen's expectations for how a dog should act constantly adapting to the Dalmartian's needs and vice versa. Give this picture book to imaginative kiddos who might wonder what fantastical shenanigans their adopted pets were up to before settling down with their families.