Great Squarerebula is the mutated fusion of Doctor Square and Iron Cerebula and is the final boss of Rocketboy 2: Fallout. Doctor Square fought Rocketboy in an epic battle. However, Doctor Square's fortress was crumbling and they fell, Doctor Square and Iron Cerebula fell into a pool of TOX-N, the TOX-N mutated and fused them into Great Squarerebula. It can shoot missiles from it's mouth and turn into a battering ram. It can also use the combined powers of both.