Halo: Reach is a 2010 first-person shooter from Bungie for Xbox 360, and its multiplayer medals come with short announcer callouts that mark notable feats during a match. Killjoy is one of those medal callouts, tied to stopping an opponent's run, and players quickly clipped it for montages, streams and soundboards. Because it is only about a second and a half long, it is easy to drop into edits without breaking pace, and its association with Halo's competitive multiplayer keeps it recognisable to longtime fans years after release.