David Bullock, famously known as "The .38 Caliber Killer" or "The Happy Killer," was an American serial killer who shot and killed at least six people in New York City over a one-month spree between December 1981 and January 1982. When he pleaded guilty to the crimes, Bullock chilled the courtroom by smiling and stating that he committed the murders simply because he "felt the Christmas spirit", adding that killing made him happy and gave him a sense of power over his victims.