With Halloween 2011 just under a week away, many stars -- like Justin Bieber -- are putting the final touches on their costumes. 'Glee' famer Chris Colfer, who portrays the favorite Kurt, visited 'Conan' on Monday to declare war on fellow Halloween party-goers, but also admitted to a (not so) surprising fear of teenage girls.

"I have a rule with myself. Every Halloween, I have to make my own costume," Chris revealed to Conan and his audience. "I've done that for the last two years, and there's one party that I go to where I win every year." Last year, the 'Glee' star went to his annual costume contest party as Los Angeles (complete with the 401 traffic). The year before, he was a very creative Venus fly trap.

Though Colfer didn't spill his costume plans for 2011, he did reveal something that really frightens him: teenage girls. "There is nothing more terrifying than a teenage girl. They have so many feelings and so many emotions at once," he said, referring mainly to young female gleeks. "Sometimes I'll look at my Twitter or Facebook or whatever, and there are so many girls who will say, 'Everytime I look at your face I cry,'" he joked, which caused Conan to giggle wildly. "I don't know why they cry -- but that's something they should probably discuss with someone. It's flattering, I guess."

As if the girls aren't scary enough online, Chris implied that they can smell fear in person. "You never know what to expect from them! Sometimes they're calm at first and then they pounce on you. It's like being on Animal Planet constantly with teenage girls."

'Glee' returns to FOX on Nov. 1.

Watch Chris Colfer on 'Conan'