Ghosts of Mars

Ghosts of Mars is a 2001 sci-fi/action/horror film directed by John Carpenter.

It's 2176 and Mars has been terraformed to have a breathable atmosphere by some matriarchal mining corporation. A crack-squad of Space Police consisting of Melanie Ballard (Natasha Henstridge), Jericho Butler (Jason Statham), Bashira Kincaid (Clea Duvall) and Helena Braddock (Pam Grier) is sent to reallocate notorious criminal James "Desolation" Williams (Ice Cube), only to discover that half the colony has been possessed by the spirits of the alien race that used to inhabit Mars which were released via a scientific excavation, causing them to transform into a clan of sadomasochistic self-mutilating punk savages that look as if they're auditioning as extras for The Road Warrior and which murdered the other half. The rest of the movie is spent fighting them and... that's really about all there is.

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This film provides examples of:

 * Black Dude Dies First: A triple-header. Braddock is black, a woman and a lesbian.
 * Butch Lesbian: Helena.
 * Complete Monster: The punk martians, expecially their leader. They love to chop their victim's head and put the face on like a mask.
 * Demonic Possession: Which makes killing the crazy people a bad idea. Not only will the evil spirit possessing them escape -- it might relocate into you.
 * Drugs Are Bad: Subverted; the fact that she's taking "clear" allows Mel to fight off the alien spirit possessing her.
 * Fetish Fuel Future: While it's not explored in detail, a black leather-clad Lady Land where hot girl-on-girl action is implied to be a prominent form of career advancement certainly qualifies.
 * Foregone Conclusion: You might notice this trope at play as soon as we find out how the alien spirits operate. There is NO discernable way to kill them, and they will just continue jumping from body to body if their current host is killed. This means that in order to even temporarily defeat them, our heroes would have to kill every human being on the entire planet of Mars, including themselves. Guess which side wins?
 * Ghost Town: The mining town.
 * Gorn
 * Invincible Villain: See also Foregone Conclusion above. The titular ghosts are just that - intangible ghosts, who possess humans to interact with them. The spirits can't be killed by any known means (they even tried a nuclear detonation, which did nothing), which means that if their host is destroyed they'll just move on to the next body. The movie dances around this issue by setting up the all-out battle to occur after the story's events, but it's impossible to maintain any hope for the surviving characters because victory is ultimately impossible.
 * Lady Land: The human society on Mars is explicitly stated to be a matriarchy, and women are primarily seen in powerful positions. Doesn't stop the men from acting like machos, though.
 * Large Ham: The leader of the punk savages, "Big Daddy Mars."
 * Leeroy Jenkins: Come on, you mindless mutherfuckers!
 * Nigh Invulnerability: Fourth variation for the evil aliens.
 * No Celebrities Were Harmed: Big Daddy Mars looks a lot like Marirlyn Manson.
 * Nuke Em: The heroes resolve to dispatch of the punk savages by blowing up the local nuclear power plant.
 * Off With His Head: One of the punks' favorite methods of killing is by decapitation, especially using sharp metal frisbees.
 * The Omniscient Council of Vagueness: The Matronage.
 * Proud Warrior Race Guys: From Melanie's hallucination; look's as if the extinct aliens were this.
 * The Red Planet: It's right in the title.
 * Rule of Cool: What the movie was clearly aiming for.
 * Sassy Black Woman: Helena (Pam Grier, of course).
 * Sealed Evil in A Can: The Martian spirits.
 * Shout Out: When Braddock shouts "Who goes there?", it's a reference to a short story with that title by John W Campbell, which has been made into a film twice, once by John Carpenter as The Thing.
 * Space Police: Most of the main characters have this occupation.
 * Traintop Battle: The finale.