Whelp I guess the Skag's outta tha bag. An early tweet from "Borderlands 2" lead writer, Anthony Burch, has forced Gearbox to prematurely debut the 4th DLC for the boisterous loot 'n' shooter!
I've already seen (and played!) the expansion but unfortunately you'll have to wait a little longer for my full impressions. However, I can toss a few details your way:
The 4th DLC is called 'Tiny Tina's Assault on Dragon Keep' and it revolves around a spoof of a certain popular tabletop RPG hosted by everyone's favorite explosive tween -- Tiny Tina! Releasing June 25th, it's included with the season pass; but if you've been more discretionary with your purchases, you can pick up for $9.99 or 800 MS space bucks.