The 'Think Fast, Chucklenuts' meme originates from the character Scout in Valve's first-person shooter Team Fortress 2. The phrase is one of the Scout's voice lines triggered when he throws a projectile, specifically popularized by a viral series of 'flashbang' videos where the screen suddenly turns white after the line is delivered. It gained massive traction on platforms like YouTube and Discord in the early 2020s as a 'bait-and-switch' or jump-scare video format. Today, the meme is widely used to catch viewers off guard or to represent a sudden, overwhelming situation, often paired with a blinding white screen to mimic the effect of a tactical stun grenade.