The Dark Crystal is a 1982 fantasy film created by the Jim Henson Company (which means its entirely puppets!)
Most people remember this movie as childhood nightmare fuel but I've always loved it (for reasons i'll get into in crystal 2!)
The Dark Crystal was one of the Henson Co.'s attempts to display that puppetry wasn't a 'kids-only' medium. This movie has a lot to say about Balance, Death, and our relationship with the environment. The 'scary' factor can partially be attributed to the uncanny valley effect produced by some of the more lifelike puppets, as well as the fantastical realism of the Skeksis.
since the movie's debut (and mixed reviews :'/) in '82, there has been a novelization, several comic books, and a recent (cancelled) netflix series.
Two Gelfling orphans, the last of their kind, are tasked with reuniting a crystal shard with The Dark Crystal, a powerful magic stone, in order to get their planet free from the vicious Skeksis. By reuniting the shard with the Crystal, they heal the Crystal and their planet back to their original states. The characters do not remain unchanged by their quest.