Final Fortress

The Final Fortress (最終的な要塞 Saishū Teki na Yōsai) is a giant whale shark-shaped battle flagship that makes its first appearance in Sonic Heroes as the final stage, and as three different racing tracks in the racing game Sonic & Sega All-Stars Racing. Final Fortress is located in the heart of the Egg Fleet, and seems to be permanently surrounded in rough weather. Modern Sonic fights the Egg Emperor in Final Fortress in the Nintendo 3DS version of Sonic Generations.

Description
This massive ship is the Flying Fortress. It is in the shape of a massive whale shark and is much larger than any of Eggman's flying fortresses. The Final Fortress was heavily armed, and could have easily been the equivalent of the rest of the fleet in size and armament. From a birds-eye view, the Final Fortress appears to be a small city carried on the back of a giant flying whale. The ship's bridge is located atop a large spire that resembles Dr. Eggman's face. Final Fortress seems to be permanently surrounded in rough weather. In the very core of the flagship lies a giant structure with a mechanical version of Eggman's head on top, hiding the power core of the vessel.

Sonic X
Final Fortress appears in the Sonic X anime. It a giant whale shark-shaped battleship and Dr. Robotnik's highly technological mobile fortress. It served as Robotnik's flying fortress of operations on Earth and Dens as the doctor plotted to take over the planet.