Chuck tells Dean that when he gets back to 2009 he should hoard toilet paper, hoard it as if it was worth its weight in gold, because when the Croatoan pandemic started toilet paper quickly became a rare and precious commodity. This actually turns out to be somewhat prophetic for real life: when the 2019 Coronavirus pandemic started one of the first things people started panic buying was toilet paper. Most stores limited the sale of toilet paper to each customer, which resulted in a number of situations where people in stores started fighting over toilet paper, with some of the fights becoming violent and videos of them went viral on the internet.
When Sam tells Dean he's Lucifer's vessel Dean says, "Just when you thought you were out, they pull you back in." This is a reference to The Godfather Part III (1990) when a retired Michael Corleone says, " Just when I thought I was out, they pull me back in!"
The sign outside the movie theater when Dean first wake up in 2014 days "Now Playing Route 666". One of the stars of the film Route 666 (2001) is Steven Williams, who plays the hunter Rufus in Supernatural.
"The End" is the final song on The Doors self-titled album and includes the following lyrics;
"Of our elaborate plans, the end Of everything that stands, the end No safety or surprise, the end I'll never look into your eyes...again"
"Of our elaborate plans, the end Of everything that stands, the end No safety or surprise, the end I'll never look into your eyes...again"