Ok, so technically they're "Husks," but if it looks like a zombie and talks like a zombie, then what is it? Don't strain your brain too hard on this one.
Anyway, this trailer - courtesy of G4 - is two minutes and 43 seconds of fast bullets chasing down slow zombie-husk things. Shepard may have a quick tongue on him, but we have to admit that explosions and gunfire make for a better trailer.
Check it out for yourself after the break.