The phrase comes from Among Us, the social deduction game released by Innersloth in 2018 that surged in popularity in 2020. Players shortened suspicious to sus and used it during emergency meetings to accuse crewmates of secretly being the imposter tasked with eliminating the crew. As clips spread on TikTok, Twitch and YouTube, sus escaped the game and became general internet slang for anything shady. This stretched, disbelieving version keeps that meeting-room accusation alive as a standalone reaction sound.