What could be funnier than a giant elephant sitting on a tiny bird egg? A cat wearing a pomelo, that's what. But Seuss didn't have the Internet, so we get an elephant on an egg.
Hilarious, yes. But at the same time, Horton Hatches the Egg brings up issues like child abandonment, forced migration, and the ethics of war. Makes sense, too, since Seuss was in the middle of some heavy times when he wrote the story. He'd recently learned that he and his wife would be unable to have children of their own, and he was very concerned about what we now know as World War II.
Of course, Seuss can't help but lighten the mood, even when poor Horton is experiencing dark moments:
And the first thing he knew, they had built a big wagon
With ropes on the front for the pullers to drag on.
They dug up his tree and they put it inside,
With Horton so sad that he practically cried. (127-130)
Shmoop is experiencing some very mixed emotions. We want to laugh at the absurdity of the whole thing—the tree is in a pot, for crying out loud—but we can't because it's just so sad for poor Horton. We're hopelessly caught between gravitas and levitas. And that's the magic of Seuss.