Star Trek has always been a franchise built on big ideas. It pushed boundaries from the start and it kept raising the bar with every series and film. But not every bold idea made it to the screen.

Star Trek canon is grounded in concepts of the UFP as a union of planets that share common goals of maintaining peace and diplomacy (including rules of warfare), exploration of the galaxy ...

The "Alien" movies are marked by their cynicism, usually depicting shifty, profit-driven company men who aim to retrieve alien xenomorphs for nefarious purposes, no matter the human cost the retrieval ...

The Horta were an illustration that there are plenty of life forms in the Star Trek universe that are not remotely humanoid.