M850 Grizzly

Grizzly "The heavily armored Scorpion tank inflicts massive damage with its primary cannon, but struggles to track fast-moving targets. One of the special Corps upgrades, the Grizzly, adds a double-barreled cannon and a flamethrower that can roast surrounding troops."

- GamePro, July Edition

The Grizzly is a variant of the M808B Main Battle Tank. It is set to appear in Halo Wars, accessed by upgrading the Scorpion, and usable only by the UNSC "Corps" Faction.

Overview
The Grizzly is a variant of the Scorpion, used in combat only by the UNSC Marine Corps. Instead of the standard Scorpion armament (a one-barreled cannon), it's armed with a double-barreled cannon and a deadly flamethrower. This suggests the Grizzly is for Tank Commanders or Special Forces Units.