Not only is the Mohawk Grenade real and in-game, but Mr. T put it there. That's what we learn in this new commercial, a sequel of sorts to the old "Night Elf Mohawk" joke a long while back. Not only is T (not The T, just T) decked out in a Murloco's Taco's T-shirt, but he shows the in-game item in action. It's how he makes the World of Warcraft look good.
I love it -- well done, Blizzard. Great kickoff to the holiday marketing season, and it's awesome that they've got the commercial (which we assume you'll soon see on television) promoting the actual in-game item in a quality way. Sure, The Old Republic and a few other MMOs might be knocking on WoW's door, but who wouldn't want to play a game where you can throw a grenade and make people look like Mr. T? Maybe this is where all those newbies will be coming from.