Headmasters tend to look like this.

The Headmaster is a character in "Adjunct Professor What?", featured in the episodes "Tick Tock Timelord", "One Professor, Two Professors, Three Professors, Potato", and "That's a Train". Though often confused as the villain The Master, The Headmaster is just a simple, helpful school principal. Much to the Adjunct Professor's confusion, he also carries a pocketwatch and "asks far too many questions" ("That's a Train") The Headmaster was eventually eaten by a street gang of very hungry and uneducated evil monkeys, known as the Banana Bunch.