The line comes from Dota 2, Valve's multiplayer battle arena game released in 2013, where announcer calls mark escalating kill streaks during a match. Holy shit is reserved for the highest streaks, so players rarely heard it in normal games, which made the clip feel special when it did trigger. As Dota highlights and Twitch clips spread across YouTube and Discord, the female voiced version was ripped as a standalone reaction sound, and it is now used far beyond Dota for any play that looks impossibly dominant.