Commander Toad in Space — Jane Yolen

Young fans of Star Wars and silliness will toad-ally love Commander Toad
Brave Commander Toad and the crew of the spaceship Star Warts have a mission: they must go where no spaceship has gone before and bring a little bit of earth out to the alien stars. But when they try to land their sky skimmer on the planet made of water, a terrible sound rises from the waves. Deep Wader is not pleased at being disturbed. "This planet belongs to me," he roars. It looks as though the crew of the Star Warts might become the monster's lunch.