The Russian enforcer on the motorcycle who keeps coming for Hopper like a silent killing machine ( Andrey Ivchenko ) bears a striking resemblance to Arnold Schwarzenegger’s character in James Cameron’s 1984 sci-fi action thriller, “The Terminator.” The supernatural goop that slides through the bars of the rat cage in Episode 2 and under the door in Episode 6 could be a nod to “Terminator 2: Judgment Day,” but that could also be coincidence: The Duffers seem to mostly reference films and TV shows from before or during the era in which the show is set; “Terminator 2” didn’t arrive until 1991.

‘The Thing’

We know Mike (Finn Wolfhard) is a fan: The poster for this 1982 horror masterpiece from John Carpenter — a remake of “The Thing From Another World” (1951) — has been hanging in his basement since Season 1. But the movie is also referenced by Lucas when the gang is in Bradley’s Big Buy. (Much to the dismay of his friends with better taste, Lucas compares it favorably to New Coke.) Billy and others are taken over by a force not unlike the alien of “The Thing,” and the Mind Flayer bears a striking resemblance to that alien as well, not least because of its spider-like legs.

Wonder Woman

Max introduces El to “Wonder Woman” comic books at the start of Episode 4, telling her about Princess Diana and her life in a place filled with only Amazon warrior women . Perhaps the comics helped give El the confidence she needed for her own heroism in the final episodes.

The X-Men

Dustin calls his high-powered machine Cerebro, a name-check to the device used by Professor X in this Marvel Comics series to find mutants around the world. The device first appeared in the comic books in 1964 and is still a major part of the X-Men mythology, playing a role in recent print editions and feature films.