The Phantom Tollbooth
What is an antagonist anyway? Well, it's generally the person or thing that prevents our protagonist from overcoming his conflict. So, since our conflict is boredom, we have to ask: what prevents Milo from overcoming his boredom? Shmoop is going to take a leap and say that it's ignorance that does the antagonizing. Ignorance is what Milo's facing at the beginning, when he's too bored to learn. Ignorance is what separates King Azaz and the Mathemagician, and drives Rhyme and Reason out of Wisdom. And Ignorance – literally, the place – is home to all the scary demons who try to keep Milo from reaching the Castle in the Air. Once Milo overcomes this ignorance and learns how to, well, learn, he's no longer bored. See ya later, conflict.