Ice Boy by David Ezra Stein

Ice Boy wants to explore the world outside the freezer in a big way, starting his adventure at the beach, where he becomes Water Boy. Washing up on big swell, he soaks someone's towel. As he basks in the sun, he begins to steam... This leads to a journey high in the sky as Vapor Boy. A storm returns him to his original form of Ice Boy, hurtling him back to earth where he has the good fortune to land in a glass of water - right next to his parents!
The whole cycle starts all over again, this time for the parents and son, after the drink gets tossed on the lawn and the sprinkler goes on! Yes, it's weird but it's also wonderful and my students, from grades 1 - 5, loved it!
Source: Review Copy