Don’t expect a straightforward timeline, because continuity is a mess with the Alien and Predator timelines (even if, as in this list, you choose to ignore tie-in comics, novels, and games). Predator: ...

Some exceptionally unsettling elements were thrown together to create the Xenomorph when it first appeared in Ridley Scott's 1979 horror sci-fi, "Alien." Spliced from the nightmares of artist H.R.