The Mammoth only ever appears in the campaign during the mission Reclaimer. It is a large vehicle that has three indoor floors as well as a top side with various weapons and turrets. On the bottom floor is a bay area with a couple of warthogs. On the appear levels near the front are weapon mounts with various weapons such as Battle Rifles and Sniper Rifles.
It is a great place to fight from but since you have no control over the vehicle, your control of its use is limited.
