Tock the Watchdog

Tock the Watchdog is a highly intelligent watchdog and the closest friend of Milo. He ends up getting captured by the princesses, and is used as a personal servant throughout the story.

Backstory
What is known about Tock in the Phantom Tollbooth, is still known here, but there is more uncovered about him. Tock lost his way home when he used to live in Caniburg, after a freak accident that happened on his father's plane (the plane is a grandfather clock) back in 1959. (That's how he ended up in Dictionopolis) How that happened is that he flew off of the plane by accident and was never seen since. Later in the story, Tock is reunited with both his parents, once Tock was freed from the princesses.