Mervin the Sloth is just standing there quietly when giant letters drop onto the page: "Mervin the Sloth is about to do the best thing in the world." But what is the best thing in the world? What is Mervin about to do? It doesn't take long for all of Mervin's exuberant animal friends to barge in with their own ideas. Flying Digging Gazelling Wait, gazelling? Is that even a word? If only sloths weren't so slow Because maybe it's...