'Execute Order 66' comes from Star Wars: Episode III – Revenge of the Sith, released in 2005, when Chancellor Palpatine gives the command that triggers the Jedi purge. The line became a lasting meme because it is short, dark, and easy to apply to any sudden betrayal or ruthless decision. It spread widely through YouTube compilations, gaming edits, and short-form meme videos, where creators use it as a dramatic cue for backstabbing, elimination, or an abrupt change in loyalty.