Though their day jobs often involve a plethora of costumes and hours in a makeup chair, many of our favorite sci-fi stars still enjoy stepping out in costume for a good time on All Hallow's Eve. So for the 31st—and final—of our 31 Days of Halloween features of 2012, we take a peek at the Halloween duds of nearly 20 sci-fi celebs.

And here's a complete list of all 31 Days of Halloween features:

9 zombie-killing ladies we want on our side during the apocalypse

11 custom coffins perfect for any sci-fi fan's final collectible

12 movie and TV haunted houses we wouldn't mind moving into

10 unsettlingly scary movies in which everyone dies at the end

8 undead animals prove reanimation ain't always such a good idea

14 timeless literary classics mashed up into creepy horror tales

Nosferatu + 13 more classic silent horror films you can watch NOW

Gruesome Halloween costume ideas from 25 terrifying cosplayers

12 deadly TV psychos we should hate (but secretly love)

11 weird zombie-killing weapons that'll destroy the undead with style

15 Lovecraftian stories to read once you've read all of Lovecraft

Watch 9 over-the-top horror movie performances by Star Trek stars

11 zombies it hurt to kill because we loved them so much

Mickey, Popeye and more get spooked in 15 classic creepy cartoons

20 horrifying, hilarious Halloween T-shirts better than costumes

11 great, gory vampire kills from horror movies and TV

Dracula's Dog + 8 more WTF movies about the Prince of Darkness

15 awesomely horrific Game of Thrones deaths (+ a bonus LOL one)

Batman, Iron Man + 22 more superhero-carved Halloween pumpkins

8 horror movies inspired by Native American myths and legends

Beetlejuice, Slimer + 9 more goofy ghosts from horror films and TV

12 most annoyingly useless horror movie authority figures

13 horrific Kickstarter projects you can help fund before Halloween

12 gruesome horror scenes where someone loses a head

Chomp down on 23 awesomely revolting zombie comic book covers

9 spooky body mods that'll put your Halloween costume to shame

14 annoying horror movie victims we were actually glad to see die

9 over-the-top horror films so disgusting they got banned

Check out 13 scary move trailers that still freak us out

25 creepy cosplayers who should be horrific but are sexy instead

See Harrison Ford + 18 more sci-fi celebs in Halloween costumes