Fuse's Lair is the overall final level of the game and is where the player can find the highest level monsters, the most infected patches, and the main antagonist, Fuse. It is the most infected area in the entire game. It is only accessible via The Precipice, and the Green Maw. There are no NPCs, no shops, no Monkey Skyway Agents; nor are there any S.C.A.M.P.E.R.s. There is no infected zone in this section and only three Fusion Portals, leading to Fuse's Hall, Fuse's Labyrinth, and Fuse's Throne. Unless players have got the power and stamina, they should not go in there alone, or they will regret it!
|Boss||Great Shellslug King|
|The highest and greatest Shellslugs, they are known as the Prime Guardians of Fuse's Lair, since they go in swarms and you can see them near the bridge to Fuse's Lair. They also help with Fuse's contraptions, like the Fusion Machine to mass-produce the Fusion Kevins!|
Area: Fuse's Lair
|The Cephalopod followed Fuse to our planet, feeding on comets made of volcanic rock. They communicate telepathically and are highly intelligent. When angered they strike swiftly, and they never miss.|
|Boss||Meteoric Guardian Lieutenant|
|As alien and strange as the Cephalopods, the Meteoric Guardians arrived with Fuse from a distant world, trailing in the wake of a comet and feeding on the ice and water. It is believed they can kill you with a single thought.|