Metal Gear REX is the nuclear-armed walking tank from Metal Gear Solid, first released in 1998, and this clip captures its first roar during its dramatic introduction in the game. The sound was designed to make a machine feel like a living predator, mixing animal-like growling with heavy mechanical noise. As clips from the game spread through soundboards and video edits, the roar became a shorthand for something huge and dangerous waking up, and editors still use it today for reveals, boss introductions and over-the-top reaction moments.