Great Force is the boss of zone M in Darius Force. It is shaped after a humpback whale.
Much like Great Thing, Great Force's body is covered with cannons, all of which must be destroyed before you can harm the boss. It also fills a good portion of the screen, forcing the player to circle around him in order to target the cannons, which will obviously be shooting constantly while the boss moves around. Once the cannons are destroyed, Great Force will attempt to ram the player and use a spitting attack.