You like free things right? Even if they're virtual? Gearbox knows you do. Gearbox Software has been giving out codes through their Twitter and Facebook for Halloween themed Borderlands 2 character skins all day.
If you're freaking out, thinking you've missed them, don't worry. Unlike golden keys, the skins will be active for quite a few days—all the way until Sunday, November 4th at 11:55PM CT (you can find out when that is for you here).
At the time of this article, Maya, Salvador, and Axton's codes have been released. Zero's is coming up in a few hours. The skins seem to all have a theme of a type of stinging yellow and black bug. Maya's is called Fright of the Bumblebee, Salvador's is Killer Bee, Axton's is called Yellowjacket and Zero's is Hornet's Nest.
You can find the corresponding SHiFT codes here.