Finalhazard

The is the Biolizard transformed by fusing with the Space Colony ARK. It is the final boss of Sonic Adventure 2 and Sonic Adventure 2: Battle. After Sonic the Hedgehog and Knuckles the Echidna stopped the Space Colony ARK from colliding with the Earth on its own, the Biolizard used Chaos Control to teleport outside the ARK, and became the FinalHazard in order to keep the ARK on its crash course. It was ultimately defeated by Super Sonic and Super Shadow. The song Live and Learn is played during the battle with it.

Appearance
Having essentially become the Space Colony ARK by merging with the ARK's Eclipse Cannon, the FinalHazard is one of the largest entities in the Sonic series by far, with most of its body being the Space Colony ARK. At the point of the Eclipse Cannon, the FinalHazard's organic body can be found, which is the Biolizard's entire body, having fused at where the Biolizard's tail would have been to the tip of the Eclipse Cannon. The FinalHazard's original body, however, displays severe damage; the cables on the left side of its head and the back of its body has been torn off and it has a stump, where its left foot would be.

History
After the Biolizard failed to stop Sonic the Hedgehog and Knuckles the Echidna from using the Master Emerald to stop the Chaos Emeralds from giving the Space Colony ARK the power needed to collide with Earth and destroy it, the ARK was briefly stopped in its tracks.

Acting upon the orders giving by the late Gerald Robotnik, however, the Biolizard used Chaos Control to teleport outside the Space Colony ARK's central core by using the power of the seven Chaos Emeralds. Once outside the ARK, the Biolizard merged with the ARK at the tip of the Eclipse Cannon, thus becoming the FinalHazard. Now in control of the ARK, the FinalHazard began resuming the ARK's crash course into Earth by literally dragging the ARK towards the planet. In the process, however, the FinalHazard was confronted by Super Sonic and Super Shadow and it fought them in a battle against time. In the battle, Super Sonic and Super Shadow made use of the FinalHazard's damaged life support system to inflict damage upon the monster, which eventually let to the Finalhazard's defeat, upon which small explosions began to erupt from its body.

After the battle with Super Sonic and Super Shadow, the FinalHazard became dislodged from the Eclipse Cannon, thus providing no purchase for the FinalHazard to hang on to. Its current fate is unknown, but its close proximity to Earth possibly means that it was incinerated upon re-entry into the atmosphere.

Powers and Abilities
With the power provided by the Space Colony ARK and the Chaos Emeralds, the FinalHazard was quite a challenging enemy, as it took the power of both Super Sonic and Super Shadow to defeat it. Its powers included firing up to two large pink lasers with wide range and creating dozens of purple eggs with asexual reproduction abilities to use both as projectiles and to shield itself, both of which have enough power to repel a super transformed character over large distances. It also have regenerative powers, allowing it to heal damages and making itself nearly invulnerable.

Due to being physically connected to the Space Colony ARK, the FinalHazard can control the entire ARK, though it has not been shown to what extend other than controlling the ARK's crash course.

Unfortunately, the Finalhazard's enormous power came at a price: in its previous battle with Shadow the Hedgehog and in the transformation process, the FinalHazard's life support system became damaged and it therefore had to draw power from the Space Colony ARK in order to maintain itself. This also caused large red boils to develop on its skin, which caused the FinalHazard great pain and physical damaged if attacked.

Sonic X
The FinalHazard appeared in the episode Showdown in Space in Sonic X. Just like its role in the games, the Biolizard became the FinalHazard in the last-ditch effort to keep the Space Colony ARK on its crash course with Earth. After using Chaos Control to teleport outside the ARK, the Biolizard's upper body began growing out on the tip of the Eclipse Cannon, allowing it to become the FinalHazard, where it kept the ARK on its collision course. Shortly after, however, the FinalHazard was confronted by Super Sonic and Super Shadow and fought them. After a brief battle, the FinalHazard was killed when Super Sonic and Super Shadow blew up its life support system, which caused a explosion that burned the Finalhazard to smithereens.

Archie Comics
The FinalHazard also appeared in the Archie Comics's adaptation of Sonic Adventure 2. While the FinalHazard chronologically appeared between Archie Sonic the Hedgehog Issue 98 and Archie Sonic the Hedgehog Issue 99, however, it was not until Archie Sonic Universe Issue 2 that it actually appeared in the comics.

Much like in the games, the Biolizard transformed into the FinalHazard in order to keep the Space Colony ARK on its collision course with Mobius, but was defeated by Super Sonic and Super Shadow.

Battle
The battle against the FinalHazard is fairly simple. During the battle, the player takes control of both Super Sonic and Super Shadow as they take turns battling the Finalhazard. In order deal damage to the FinalHazard, the player must use the Super Sonic Boost to ram into the Finalhazard's pink boils. After each hit, however, the FinalHazard will make it more difficult for Super Sonic and Super Shadow to get close by shooting laser beams or launching its purple eggs.

After damaging the FinalHazard, the character the player controls switches, though the player can also switch manually by flying over the FinalHazard. As with all super transformed, Super Sonic and Super Shadow lose one ring for each past second, and if one of them run out of rings completely, the controlled character will revert back to normal and the player loses a life. In order to have one character collect more rings, the player has to switch to the other character, and the first character will collect more rings while the player controls the other character.

Once the Finalhazard receives a total of six hits, it will be defeated.

First Round
During the first part, the FinalHazard basically does nothing until the player gets close. Once the player does, it surrounds itself with the nine eggs (three in a row) It is relatively simple to maneuver around this and hit it.

Second Round
The FinalHazard starts shooting laser beams from its life support system that the player has to maneuver past. If the player gets hit by it, he/she will not be able to move for about 5 seconds.

Third Round
Same as the second round (See above).

Fourth Round
The FinalHazard will surround itself with its eggs, though in a denser field, and shoot lasers. The eggs will slow down the player as well.

Fifth Round
Same as the the fourth round, except this time, the FinalHazard is faster and a little more erratic with its egg shooting.

Trivia

 * The FinalHazard's cry is a recycled version of that of Perfect Chaos, which was in turn also used for Devil Doom.
 * During the battle with Sonic and Shadow, Eggman referred to the boils on the FinalHazard's skin as "chloroplasts."
 * The FinalHazard is shown to have lost some limbs, such as an arm, when fighting him. This may have occurred after losing to Shadow, or when attaching itself to the Eclipse Cannon.
 * In Sonic Adventure 2 the FinalHazard was shooting lasers out of its health support system. However in Sonic X, the lasers were shot out of its mouth.
 * If the player fights the FinalHazard for more than five minutes, the player will instantly die due to the fact that the ARK crashes to Earth within that time.
 * After about 3 minutes, the screen will turn an eerie red, signifying that the ARK is gaining velocity and approaching Earth.
 * In Sonic and the Black Knight, while fighting the dragon in Dragons Lair, Caliburn says it is an enemy like no other, Sonic replies saying he had a similar battle where he was with Shadow the Hedgehog referring to the FinalHazard.
 * He is the only boss in the game where more than one super character is played as a requirement to defeat it. He shares these traits with Solaris, the Time Eater, the Egg Salamander, the Egg Wizard and Metal Overlord.
 * The FinalHazard's Eyecatch Card incorrectly names it Final Lizard.