“FBI, open up!” became a staple internet reaction sound through raid parody memes and short edits built around the idea of federal agents bursting in at the worst possible moment. The clip spread widely on YouTube, Vine-era compilations, and later TikTok and short-form meme pages because the line is brief, dramatic, and easy to time with a hard cut. It remains popular in reaction edits, prank setups, and exaggerated “caught red-handed” jokes. A common variation adds an explosion-like breach, as in FBI OPEN UP (with explosion).