Reinforcement Ready comes from Command and Conquer: Red Alert 2, the 2000 real-time strategy game by Westwood Studios, where an announcer alerts the Soviet player that new units are available. The line was one of many short in-game notifications designed to be heard clearly over battle noise, and players began reusing it outside matches as shorthand for backup arriving. Shared through gameplay videos, streams and soundboards, it has stayed popular with strategy fans and editors who want a quick, nostalgic cue that needs no explanation.