Among Us is a social deduction game developed by Innersloth and released in 2018, though it exploded in popularity in 2020 when streamers on Twitch and YouTube made it a streaming staple. Only the impostor role can travel through the map's ventilation system, so being spotted exiting a vent is an instant giveaway. Alongside game clips like the Roblox oof, the metallic exit sound spread as shorthand for 'sus' behavior, and editors now use it in videos unrelated to the game to flag someone acting suspicious or caught red-handed.