MM2 usually refers to Murder Mystery 2, the long-running Roblox game by Nikilis that became especially popular through YouTube and TikTok gameplay clips. Sounds from the game spread as creators clipped dramatic sheriff shots, last-second saves, and elimination moments into short edits. This particular effect stays popular because it is brief, recognizable to Roblox players, and easy to sync with a visual payoff. In meme edits, it often fills the same role as a Pew_Pew style shot cue, but with a more game-specific identity.