The phrase 'Boom, headshot!' comes from FPS Doug, the trash-talking gamer character in the web series Pure Pwnage, which debuted in 2004. His exaggerated victory shout became a running joke among first-person shooter players and spread through gaming forums, YouTube montages and kill compilations. Over time it detached from the show and turned into a standalone gaming meme, shouted whenever a player lands a clean headshot. It endures because it distills the thrill of a perfect shot into three syllables.