SANTA BRINGS CHRISTMAS FUN TO MARS!
Martians fear their children have become lazy and joyless due to their newfound obsession with Earth TV shows. After ancient Martian leader Chochem suggests that the children of Mars need more fun --including their own Santa Claus-- supreme leader Lord Kimar assembles an expedition to Earth. Once there, they kidnap two children who lead them to the North Pole, then capture the real Santa Claus, taking all three back to Mars in an attempt to bring the Martian children happiness.
This movie is just so bad. Not even really so bad it's good because the pacing just drags. There are moments of absolutely stupid hilarity. So if you're going to watch Santa Claus Conquers The Martians, I'd recommend the Mystery Science Theater 3000 episode. You can stream for free without commercials via the MST3K app. Anybody browsing this sub should do themselves a favor and grab that app anyway. Almost all the classic episodes are available for free.