Pig Submarine

The pig submarine is an otherwise unidentified submarine craft that saw service in the Royal Piggy Navy. It was notably used after a war between the birds and pigs ended with an emergency truce and the creation of a Bird-Pig Alliance.

Description
The pig submarine is a massive, yellow submersible craft that is several stories tall. It has two hatches, one at the top of the craft and another snout-shaped one at the front, as well as four small leg-like structures that aid in propulsion through the water in some way. The submarine also has a decoy-like structure atop her that is intended to give the initial illusion that it's a small ship to onlookers and adversaries alike. The submarine is entirely pig-shaped, having two ears as lanterns.

The submarine contains a massive technological lab, spanning multiple decks, where Guinea Pigs work tirelessly testing new gadgets under Garry's direction. Its hull and engine are capable of breaching large sheets of ice in a single maneuver.

History
After Leonard ended the Great Egg War with an emergency truce after witnessing reports of an attack from Zeta on Eagle Island, he traveled to Bird Island personally on his submarine to confirm his truce to the Birds. After convincing Red to gather a Bird-Pig strike team and forge an alliance to prevent Zeta from destroying both islands for her to expand her resort upon, Leonard then led the strike team to Bird Island Beach and summoned the submarine from the shores. The team promptly boarded the ship, raised a Pig and Bird flag together to formally declare their alliance and sailed into Eagle Island undetected.

Onboard the submarine en route to their mission, the strike team took part in various team-building exercises, and later were introduced to gadgets invented by Garry that would be believed to be helpful or crucial in completing the mission. The submarine then arrived in the waters nearby the island, crashing through the thick ice to secure an entrance. The front snout-like hatch then opened to allow the strike team to immediately step onto the island, but the hatch door they had to walk through was inexplicably too slippery, causing all team members to slide and tumble across it onto the snow in front.

After the mission was successfully completed, the submarine was implied to be used to bring back all team members to Bird Island for celebrations.