This ship's the size of a city, chock-full o' henchpeople of the Shadow Boss and the Dark Queen and packed with enough ordnance to invade a galaxy. 'Nuff said! - Official description from the manual.

The Colossus is a rat-shaped, city-sized spaceship that serves as the primary setting for most of Battletoads & Double Dragon: The Ultimate Team. The first stage in the game is set on the tail of the ship, with the second and third stages taking place in the ship's interior. For Stage 4, the game switches from the usual beat-'em-up format into a shoot-'em-up (patterned after Solar Jetman, another game developed by Rare), in which the player must destroy the Colossus with his own spacepod. When the Colossus is destroyed, it launches a giant missile towards the Earth, which the player must disarm in the next stage.