Milo's closest friend in the Lands Beyond, Tock, is a watchdog—a canine with a clock for a body. He spends most of his time patrolling the Doldrums, since so much time is wasted there, and decides to accompany Milo on his quest to rescue Rhyme and Reason. Tock is initially very gruff and gives Milo something of a scare when they first meet. Later, he warms up and explains that people expect watchdogs to be mean, and so Tock tries to live up to that expectation.
Being born into a long line of watchdogs, Tock believes in the value of time above all else. His purpose in life is to make sure that time is used wisely since there is, contradictorily enough, so much and yet so little of it. Tock is extremely dutiful, and it seems as if he never rests from his job and devotes all of his energies to his work as a watchdog.
When Milo first meets Tock, he is in sore need of Tock's help. The little boy has a habit of wasting time on the most useless of tasks and certainly has no appreciation of it whatsoever. Thanks to his friendship with the watchdog, however, Milo leans how important it is to use time wisely. It is important to note that Milo learns his first real lesson in the Lands Beyond when Tock saves him from the Doldrums. Without Tock's help and his newfound understanding of the value of time, it is doubtful that Milo would have completed his quest. Tock also teaches Milo about the speed of time and the ways in which it can move. Milo sees how time can fly when Tock soars out of the Castle in the Air with a number of passengers on his back.