The Egg Nega Wisp, also known as the Nega-Wisp Armor in the DS version, is the final boss of Sonic Colors Wii version and penultimate boss of the DS version. The Egg Nega Wisp is a giant robot piloted by Dr. Eggman, who uses the powers of the Wisps like Sonic, and can combine them at his will. Because the Egg Nega Wisp drains Hyper-go-on quickly like the Mind Control Ray, Eggman needs to harvest Wisps constantly throughout the battle.
The Egg Nega Wisp resembles a large robotic purple Wisp with sharp pointed spines along the body and a large one over the cockpit, clear colored frowning eyes, a large razor sharped mouth with two sharp spines on either side facing upright, a cannon inside that fires purple spikes, small stubby legs around the front and sides, a long tail out the back, and two large tentacles with sharp pincers on each end that contain a pair of purple eyes making the pincers look more like mouths which it uses to fire lasers and cubes from and also to harvest Wisps from nearby with a vacuum in the hands that sucks them into large tanks located on it's back. The tanks change color depending whatever action it is performing. The cockpit is located at the front just above its eyes with a red arrow (resembling a nose) in front pointing down towards its mouth.
The Nega Wisp Armor in the DS version looks similar to the Egg Nega Wisp of the Wii version, with a few differences. Instead of having two tentacles for arms, it has one tentacle for a tail. The Nega Wisp Armor can detach the pincher on the tail use it to perform darker versions of the color powers. It also has a cannon hidden in its mouth that it uses for specific Wisp powers. For example, the cannon fires missiles at Sonic when using the Violet Void power. The cannon can also fire a large blast when it loses all of its Wisp powers.
Because the Egg Nega Wisp is powered by Wisps, or more specifically, Nega Wisps, it uses the color powers of the Wisps in battle. In the Wii version, the Egg Nega Wisp uses Spike, Cube, and Laser Color Powers to attack. It fires the Blue Cube power to launch Cubes at Sonic, the Pink Spikes power to launch Spike balls on the ground, and the Laser power to fire Laser from its hands. It also combines the Cube and Spike powers together to make spikes attack Sonic, and Laser with Cube to make the laser reflect off the cubes and hit Sonic. It might use Frenzy to get far from Sonic,and possibly make it activate its wisp powers, due to at the beginning of the battle you hear the announcer say "Frenzy!"
In the DS version, it uses Burst, Rocket, Drill, Laser, and Void Color Powers to attack. When using Burst it gets close to the platform, charges the attack and shoots a purple flame across the screen. When using Rocket it gets under the platform and shoots 5 rockets, the 5th one Sonic has to boost into. When using Drill it gets into the middle of the screen and whips the drill around the platform, and falls to the platform giving Sonic a chance to boost into it. The Laser power lets its claw shoot a laser repeatedly, before charging up a final, more powerful laser, giving Sonic a chance to boost into it to let its claw shoot itself. When using Void, its claw will go to the left off the platform, and the Nega Wisp Armor will go to the right of the screen shooting missiles at Sonic. He needs to boost into it to stop the attack.
When it needs to use another attack, the Egg Nega Wisp's arms will suck up nearby White Wisps into itself through a vacuum in the claws. After it launches an attack (or chain of attacks, depending on how far through the battle the player is), Sonic has a chance to perform a homing attack chain going up its arm and strike at Eggman in the cockpit. Right after this, Sonic can boost to hurt him again using White Wisps gained every time he hits him. At various points during the boss battle, Sonic will recover the color Wisps that Eggman used to his side, but they merely float alongside him. Rings will also spill out with every hit. When the mecha is on the brink of defeat, Sonic combines the color powers of all the Wisps he's saved to perform a combination attack called the Final Color Blaster, which defeats the Egg Nega Wisp and sends Eggman flying.
- Unlike the Wii Version, in the DS version, when Sonic saves a colored Wisp from the Egg Nega Wisp, it loses the power of the colored Wisp; and when all the Wisps are saved, Eggman uses a suicidal assault by firing a black hole cannon that was hidden in the robot's mouth.
- Unlike the Wii Version, the DS version's Nega-Wisp Armor has only one arm instead of two.
- During the Wii battle, the announcer sounds perfectly normal, but in the DS version, the announcer gets an eerie, distorted voice. The latter is probably done to imply the "Nega" aspect of the Wisps. Also, despite the Nega Wisp Armor using Nega Wisps, the announcer does not add Nega before the Wisp power, like "Nega Laser!"
- Unlike most other final bosses, this boss has an extra stage after it.
- This is the first final boss in the modern era to feature as one of Eggman's robots.
- The Egg Nega Wisp is similar in appearance to the Sand Scorpion from Sonic and the Secret Rings. Interestingly enough, their attack methods are similar as well, as with the Sand Scorpion you had to use the Homing Attack to move up its tails to hit the eye on its back, whilst with the Nega-Wisp Armor, the method is the same except performed on the arms to reach the head instead.
- The Cyan Laser is the only Color Power that the Egg Nega Wisp uses in both versions of the game.
- In the DS version, the Cyan Laser attack bounces off walls similar to how Sonic uses it.
- When the Egg Nega Wisp recharges, it seems to suck up only White Wisps.
- You can attack the Egg Nega Wisp a second time by boosting into its body after attacking the head, similar to the Egg Beetle. You also gain rings to collect and one Wisp.
- In the Wii version, before the battle starts, if you walk into the help marker to the left of the path, you can actually hear Tails talk, but briefly, and barely, talk in understandable language, warning Sonic that the Egg Nega Wisp is very powerful and that Eggman is dangerous in the Egg Nega Wisp.
- In the DS version this is not the true final battle of the game; the Mother Wisp is fought afterwards, when Sonic has collected all the Chaos Emeralds.
- In the Wii version, Eggman presses a button at the same time as Sonic uses a Homing Attack on the Egg Nega Wisp's head. This makes it seem as if the button cues Sonic's Homing Attack.
- In the Wii version, a translucent red circle is occasionally visible in the middle of the Egg Nega Wisp's left eye, possibly as a targeting system.
- In the DS version, the only way to inflict actual damage to the boss is to Boost into it.
- In the Wii version, the music is split into two phases but the battle is not. Phase 2 begins after the Pink Wisp has been collected.
- In the DS version, the Nega Wisp Armor eyes resembles Super Scourge and Metal Sonic's eyes, but are blue instead of red.
- Egg Nega Wisp's hands resemble Sonic's Purple Frenzy form.