Metallic Madness boss

Final Fever is the seventh and final boss encountered in Sonic CD, in Metallic Madness.

Once Sonic the Hedgehog enters the final arena, Doctor Robotnik will appear in his final machine, a mechanism which contains four, rotating multipurpose blades. He'll hover above the ground, spinning the blades at a quick rate, and will eventually drop down trying to crush Sonic by rotating his craft to use the blades as "feet". Eventually, he'll allow the blades to detract and use them as weapons, but this is the first advantage to defeating the boss. Once the scientist is hit, a blade will fall off, but the other blades will spin quicker than the previous time.

Like the previous phase, Robotnik will attempt to crush Sonic using the blades, and will hover back in the air to try and use them as projectiles. Another hit and the second blade is down. Upon the third phase, the doctor will try to shoot the blades from above the screen in a diagonal fashion. One hit more and it leaves the fourth blade, which spins at a super-quick speed. In a desperate, final attempt, Robotnik will use the blade as a spring to stomp on Sonic, but this proves to be a mistake, as there is no other exterior protection outside of the machine, and the last hit causes it to explode.

With that, the whole area of Metallic Madness will begin to detonate, and Amy Rose appears on the scene. Sonic will escape along with Amy outside of Robotnik's exploding fortress, and this triggers the rest of the ending.

Depending on whether or not the Time Stones are collected, the ending varies. In the bad ending, Little Planet isn't completely freed, and Robotnik will escape with a seventh Time Stone. However, Sonic will hurl a rock towards Robotnik escaping in the air, causing his Eggmobile to explode, and the whereabouts of the remaining Time Stone are unknown. In the good ending, Little Planet is freed from Robotnik's control, but the rest of the ending is the same as the bad ending.