Because of a serious lack of caffeine (due to Sam being between him and the coffee maker), Dean barely registered what his brother was telling him. He only picked it up near the end.
" . . . for some reason we were singing American Pie-you know, the old Don McLean song? And then it suddenly turned into the Weird Al version."
"What?" Dean blinked. "What are you talking about?"
"I was telling you about the dream I had."
"Why do you always feel the need to tell me about your freaky-ass dreams?"
"Just listen, okay?"
"What Weird Al version? Weird Al did American Pie?"
"Yeah, it was about the first Star Wars prequel. The Phantom Menace."
"Stop right there." Lack of coffee or not, there were some things Dean just couldn't let go. "What's the rule on Star Wars, Sammy?"
Sam rolled his eyes. "Seriously?"
"What's. The. Rule?"
The younger Winchester sighed. "Only the original trilogy counts."
"Exactly. No sequels, no prequels-except for Rogue One, cause Darth Vader kicks ass. Nothing made after 1983."
"What about the Star Wars Holiday Special?" Sam smirked.
Dean glared at him murderously. "We do not talk about the Star Wars Holiday Special."