BioWare releases "Dirty Dozen" Mass Effect 2 teaser

BioWare is really keeping their fans on a short leash with these Mass Effect 2 trailers coming out on a near-regular basis.  Their latest video is a teaser, titled "Blur" or "Dirty Dozen," depending where you catch it.

What is it a teaser for exactly?  Not just the game itself, but a full-length trailer that will be released on December 22, via Xbox LIVE.  There's no gameplay or anything, though we certainly have a solid idea of what that's like, with all the recent class videos.

"Narrated" by Martin Sheen as the Illusive Man, the Blur / Dirty Dozen teaser lets us see Shepard's new allies in their elements, doing what they do best.  We see Thane killing a small squad of guards, a Biotic (Subject Zero?) escaping confinement, and Grunt doing his people proud by taking on enemies ten times his size.  Again, this is just a teaser, and BioWare is laughing their arses off while we squirm with anticipation.