The Garapushka was constructed inside of the mountain above the Alaska base. Its range was obstructed by several mountains.
It is a 420 meter long nector cannon with the capacity to level an entire city and destroy a fleet and was powered by nectoribium. However it came at a price: a single shot required one year worth of Zogilia's mining nectoribium. Beside it took some time to charge.
The Alliance knew it was being constructed because even if it was hidden, it was too big to escape full sight. They called it the Gorgon, because they did not know its Zogilian name: Garapushka.
The Gorgon was a source of worry and its destruction the goal of the Alliance in episode 12 and 13.
The Garapushka began to charge at some point, the Alliance thus realized it was finished and immediately sent a huge fleet to destroy it. However, Alfred Gallant had devised a plan which included firing the super canon at the Alliance 1st areal pacific fleet. It destroyed or downed 50% of the fleet.
The Alliance immediately decided to send every aerial forces remaining in the first areal fleet, including the Cygnus, to destroy the Gorgon. Dio and Aoba were sent to recover their new valiancers. The commander of the Alaska base decided to shoot once again, in order to win, Margaret objected it was not the plan but he told her he was the one commanding the base. The Vajra relayed the information to Alfred Gallant who vivdly disagreed, commenting it was not worth winning a war if the country could not survive, due to exhaustion of its nectoribium reserves to power the super weapon.
The Garapushka shot once more minutes after, aiming at the energy that had appeared on the battlefield due to Hina and Aoba's coupling. The energy was sufficient to stop the nector beam but a strange reaction occurred between the two and created a time tunnel. After its disappearance, the Alliance was able to destroy the Garapushka and the Zogilian forces were forced to retreat.