Prince Of Darkness, an eerie, Nigel Kneale/Lovecraft-inspired tale set in an abandoned church, in which a group of scientists explores a vial of green fluid that may contain the Anti-God. Spoilers: they're correct.
The second was They Live, a 1988 sci-fi/action movie fronted by the late, great Roddy Piper. The movie was based on the short story "Eight O'Clock in the Morning" by Ray Nelson, and sees Piper's homeless drifter Nada discovering the world around him is secretly run by wealth hoarding aliens, who have hypnotized the planet into not being able to see him. Nada fights back against the creatures and is later aided in his battle by Keith David's Frank. The movie was a solid hit upon release but has since grown in estimation and is considered both a great genre movie and a biting political satire.
Some of the best X-Files' monster running around The White House. This cumulates in a destructive brawl between The President and Rick, which pays homage to They Live.
Rick And Morty season 3 episode 10's big fight has Rick and The President employing various gadgets and weapons, which for the former rarely comes down to wanting The President to take a selfie with Morty, to which he eventually submits. They Live famously features one of cinema's longest fight scenes, where Piper and Keith David's Frank punch it out when the latter refuses to don a pair of sunglasses that will let him see the world as it really is. They engage in a vicious brawl, where Piper's Nada eventually gets Frank to wear the glasses.
While Rick And Morty season 3 episode 10 doesn't do a shot-for-shot recreation of the They Live fight - Rick And Morty's President is voiced by none other than Keith David, further linking the episode to They Live.