Lock is the leader and one of three prime menaces to a society who could only ever dwell in Halloween Town. His other two companions, Shock and Barrel, can usually be found alongside him performing an array of acts beckoned out by Oogie Boogie — Halloween Town's ultimate form of disarray and terror. Although the Boogeyman is credited with inducing a sense of unshakable fear that has lasted for generations, Lock not only enjoys working with him, but also aspires to one day succeed him.

Lock is a force to be reckoned with despite a convincing semblance of grace and charisma. And, like most (if not all) other residents of Halloween Town, Lock has solidified his citizenship by being a legitimate monster. That being said, as it is often being mistaken for little more than an accessory to classic holiday attire, the tail that he 'wears' is actually quite real. His only true forms of costume include a single demonic mask that he wears for occasional effect, in addition to a pitch fork that makes any job he's assigned that much easier (and enjoyable) to carry out.