Roll on March 6 2012. Update: Commenter Crossngen correctly identifies the "giant worm thing" as a Thresher Maw, which I now remember fighting alongside Grunt in Mass Effect 2, though I don't ...

Thresher Maws are gigantic subterranean worms. These creatures can grow up ... Actually defeating a Thresher Maw is not required to pass the rite of passage however and merely fighting it until ...