Who are you? Silence Earthling! My name is Darth Vader. I am a...
[Marty places headphones over his father's ears and wakes him up by playing Van Halen music at full blast. George wakes up screaming - Marty pauses the music. George looks up to see Marty, who is unrecognizable because he is wearing a radiation suit]
George McFly: Who are you?
Marty McFly: [after giving him another earful of loud rock music] Silence Earthling! My name is Darth Vader. I am an extraterrestrial from the planet Vulcan!
[makes Live Long and Prosper sign with his hand]