Arclite Battalion

"Ready to roll out!"
Arclite Siege Tank from Starcraft and Starcraft Broodwar is an iconic Terran unit along with Marine and Battlecruiser. The Siege Tank is a dual mode unit. In tank mode it deals moderate damage with its twin cannons, can hit close targets and can move. In siege mode it loses ability to move and can't hit targets close to it, but gains incredible range and splash damage with the Arclite Shock Cannon.
After Brood War (i.e. in Starcraft II) Arclite Siege Tank was replaced by much-prettier Crucio Siege Tank. In addition, there also appeared modified Siege Breaker mercenary tanks, one of which is on my avatar.