Unlike many of the villains' henchmen, who are little more than disposable goons, Lock, Shock, and Barrel are actual agents of the Friends. They love to create chaos and cause trouble for the forces of good. Since Oogie Boogie is such a talented Client of the Friends, they decided to reward him with the trio of agents whose sole purpose is to assist him in his schemes. Their competence is...scattershot, but they have been effective in the past. And they have also been successful in resurrecting Oogie many times over.