The line comes from Star Wars: Episode III - Revenge of the Sith (2005), during the climactic lightsaber duel on Mustafar when Anakin Skywalker, who later becomes Darth Vader and has newly turned to the dark side, confronts his former master Obi-Wan Kenobi. After Obi-Wan declares that Anakin was like a brother to him, Anakin answers with this furious rejection. The exchange became one of the film's most quoted moments, widely shared in memes, reaction videos and edits because it captures a complete falling-out in just a few words.