Some of the best costume ideas rely not on what you're sporting on your body, but what you're wearing on your face. Case in point: this freaky-deaky look. Inspired by the Nightman in It's Always Sunny in Philadelphia, it's a fun way to scare up a quick and easy costume with whatever's in your makeup drawer. Grab some eyeliner and find out how to do it in our Halloween Challenge group. Don't forget to join and share your favorite spooky ideas.