Arnold Schwarzenegger played protagonist Alan "Dutch" Schaefer in Predator, but ultimately declined to return for 1990 sequel Predator 2.

Alien vs. Predator finally happened in 2004, but 17 years earlier, Predator 2 featured an Alien Easter egg that served to tease the crossover.

Predator 2 opened up the franchise by including a Xenomorph skull in the trophy room sequence. Here's a guide to the other skulls shown in the scene.