|This article is about the character. You may be looking for the episode.|
Finn first discovers the Box Prince's box outside the Tree Fort after a storm has passed, wondering aloud, "Does that box have a face on it?" He goes outside to investigate, and the Box Prince pokes his head out of his box and meows. Finn infers that he is lost and asks him if he knows where his home is. The Box Prince leads him to his kingdom, which is populated by other box-wearing cats. A bugle sounds, announcing the approach of the prince of the box kingdom, but Finn watches the "prince" steal from his subjects. The Box Prince makes a swapping gesture with his paws, leading Finn to believe that his identity has been switched with the thief's. Finn vows to help the Box Prince reclaim his kingdom.
Finn and the Box Prince recover the prince's crown from the woods. Finn stands on another cat's box to announce that he has found the box kingdom's "true prince," and he tapes Box Prince's crown back on, accusing the thief-prince of falsehood. However, the other cats don't believe the Box Prince, and the thief-prince challenges him to a joust. In the joust, the Box Prince and the thief-prince knock each other's boxes off, revealing that they are physically identical. They initiate a cat fight, and the entire kingdom joins in, rendering all the cats box-less.
Finn sprays the two princes with an emergency water bottle, stopping the cat fight, but then cannot tell the two princes apart. Both cats show him physical affection, further confusing him. The cats walk away, and Finn looks around at the chaotic mass of cats playing with boxes, now wondering, "Is this even a kingdom?" The episode ends with the true identity of the Box Prince unclear.
When Bandit Princess is robbing the Box Kingdom, she is shown fighting off the inhabitants of the kingdom while putting her sword through Box Prince's crown box. It is never shown if Box Prince was actually injured or in the box, but a nearby cat vomits when seeing the impaled box, so it is heavily implied that the cats thought that the Box Prince is dead.
The Box Prince is a cat with a light pink and white fur coat, and a tail covered in dark pink stripes. He usually wears a light-yellow cardboard box, which bears a tear on the top in the shape of a crown, leading Finn to believe that his crown has been lost. Unlike the other cats, his pupils are almost always dilated. The Box Prince is physically identical to his usurper. They may be related.
- The appearance of Box King's box - with a face and a crown folded out of the top - is similar to the box that Finn uses to decoy Whisper Dan in "The Silent King."
- Like the other Box Kingdom citizens, the face on the Box Prince's box changes its expression, depending on the situation.
- The Box Prince, Prince Huge, and Flame Princess' older brother and younger brothers are the only princes in the show who are not gender-swapped characters.
- The Box Prince seems to be the same breed of cat as the rest of the kingdom, as their coats are all similar in texture.