So guys i stumbled upon this event Keep an eye on the Gearbox Software Twitter and Borderlands Facebook on October 31, 2012 for SHiFT codes that unlock special spooky character customization skins in Borderlands 2 like the one above! Each code will be active until Sunday, November 4, 2012 at 11:55PM CT (What time is that for you?) To learn more about SHiFT codes and how to redeem them, visit support.gearboxsoftware.com
Funny thing is I think I already have that skin. Let me check in the editor to see if they have it. Edit: Yes they have it. http://gyazo.com/153588e9577bec938a2dc446d6c636f9