This book is The Watermelon Seed by Greg Pizzoli.

Emma has asked me to read this one over and over since we brought it home from the library. I thought it was funny and reminded me of a conversation that maiki and I had regarding how we should always tell Emma the truth, with the exception of what happens when you swallow watermelon seeds, etc. because tall tales and stories of absurdity are worth the little white lie. I love how this neurotic little alligator is so worried what is already happening in his stomach because he swallowed a watermelon seed. ^_^