Battle with the Plutonium Boss
The Plutonium Boss is merely the Emperor's pet, known as the Skelevenom.
Defeating the Plutonium Boss means releasing the Underworld Lord. It seems to be the front half of a larger creature that has broken through the wall.
The Plutonium Boss is the ultimate villain (the Underworld Lord is nowhere to be seen) in the novel, and Eve names it as the destroyer of her world, Signar-el, and many others. It's a creature that thrives on plutonium, its food source. It burrows deep under a planet, and quietly absorbs radiation for thousands of years. When it has had enough, it bursts through the surface, bathing the planet in nuclear fire. It then flies through space until it finds another source to repeat the cycle. In the book, the Plutonium Boss creates a device it calls a "cyclotron", a large machine that greatly accelerates the accumulation of plutonium, and thus the destruction of Earth. Eve states that it has no real form but instead takes on the visage of the observer's worst fear. To Jason, the Boss is described literally from the graphic seen on the book cover, rather than just the front half of a larger creature that is implied in the game. The Boss seems to be highly intelligent and is fond of taunting its foes to its last breath.
The Plutonium Boss is replaced with a similar monster known as the Skeleton Boss, which is many times larger and is fought in side view (tank) mode. At first, Jason is forced to dodge its attacks as he does not have SOPHIA with him, but once he brings SOPHIA down into the arena he can defeat the Skeleton Boss conventionally or use his new Acceleration Blast to destroy it in one strike. After the Skeleton Boss is destroyed, Jason gains access to Area 8, where the Mutant Lord awaits. Two more Skeleton Lords appear in Area 9 after Jason gains the SOPHIA Zero; one must be fought (and is notably easier than the first) and the other is a passive obstacle in a Jason-only section, and as such cannot be killed- only avoided.
|Protagonists||Jason · Eve · Roddy · Elfie · Alex|
|Antagonists||Plutonium Boss · Underworld Lord · Lightning Beings · Kaiser|
|Sophia||Sophia 3rd · 4th · J-7 · S.O.P.H.I.A. · Zero|
|Pets||Fred · Plutarch|
|Guest Characters||Gunvolt · Ekoro · Shantae · Shovel Knight|
|Areas||1 · 2 · 3 · 4 · 5 · 6 · 7 · 8|
|Upgrades||Hyper · Crusher · Hover · Key · Dive · Wall1 · Wall2|
|Subweapons||Gun · Grenade · Homing Missile · Multi-Warhead Missile · Thunder Break|
|Bosses||Mother Brain · Crabullus · Photophage · Fred · Hard Shell · Frozen Crabullus · Enhanced Fred · Plutonium Boss · Underworld Lord|