Biolizard

The Biolizard is a giant reptilian creature that appears as the final boss of the video game, ''Sonic Adventure 2. ''This genetically-engineered monstrosity was created over 50 years prior to the game's events aboard the Space Colony ARK by Professor Gerald Robotnik, the grandfather of Ivo Robotnik (aka Dr. Eggman), Sonic the Hedgehog's arch-enemy.

Creation
The Biolizard is the original prototype of Project: Shadow, an ambitious undertaking by Prof. Gerald Robotnik to create the "ultimate life-form", a first step towards eliminating disease and achieving immortality. Using reptilian DNA as the base material in extensive gene-splicing procedures, a new life-form was produced. However, the creature was far from perfect as it needed an artificial life-support system to survive. So long as the system functioned, the creature was capable of exhibiting the qualities expected of it. The Biolizard was large and cumbersome and proved to be largely immobile. This, coupled with its need for a life-support attachment, led to the ARK researchers deeming it a failure. The Biolizard was then sealed away, remaining dormant for decades until the day came when Dr. Eggman assembled all of the Chaos Emeralds aboard the ARK.

Prof. Gerald's Revenge
An unknown time after the Biolizard was encapsulated, Prof. Gerald and his staff completed their work on Project: Shadow, producing Shadow the Hedgehog. Not long after Shadow's completion, the United Federation government had declared that Project: Shadow posed a potential threat to global security and sent its elite military force G.U.N. (Guardian Units of Nations) to shut down the project. The military assaulted the space colony, executing most of the staff and even Professor Gerald's granddaughter Maria. Gerald himself was captured and taken prisoner by GUN, who would force him to make certain adjustments to Shadow to ensure the creature's loyalty, turning it into a living weapon. Driven mad by the loss of his colleagues and granddaughter, Prof. Robotnik's "adjustments" to Shadow included programming it with false memories and instructions to gather the seven Chaos Emeralds, taking them to the ARK and activating a program that would cause the colony to fall out of orbit and collide with the planet below. The program would also reactivate the Biolizard still lying dormant aboard the colony, which would defend the ARK from intruders attempting to prevent the colony from crashing. After completing his work on Shadow, Prof. Robotnik was executed for crimes against humanity and Shadow the Hedgehog remained in cryogenic stasis for the next 50 years until Dr. Eggman discovered and freed him, initiating the events of Sonic Adventure 2 and leading up to the Biolizard's reanimation.

Awakening
With the aid of Shadow the Hedgehog and Rouge the Bat, Dr. Eggman collected all of the Chaos Emeralds and installed them within the Space Colony ARK's planet-busting superweapon, the Eclipse Cannon. The doctor had planned to force the world to submit to his rule by threatening the planet with destruction, but was unaware of his late grandfather's plan to take revenge upon the world by smashing the colony into the planet. When the Chaos Emeralds were installed, the Eclipse Cannon became overloaded with Chaos energy and the ARK's orbit decayed, putting it on a collision course with the planet. The energy buildup in the cannon's core would guarantee that the explosion that occurred upon collision would completely annihilate the entire planet.

With barely half an hour before collision, Sonic the Hedgehog and his friends teamed up with Dr. Eggman to try and stop the ARK from falling. However, the Biolizard had been woken by Prof. Gerald's program and appeared within the Eclipse Cannon's core chamber to prevent the heroes from interfering with the colony's fall. Shadow the Hedgehog, who had been convinced by Amy Rose into going against Gerald's last wishes, arrived just in time to help Sonic and Knuckles reach the Chaos Emeralds by fighting against the Biolizard himself. As Shadow kept his deformed prototype distracted, Sonic and Knuckles got the Master Emerald to the core and Knuckles used it to neutralise the energy given off by the Chaos Emeralds. Reacting to the heroes interference with the core, the Biolizard used Chaos Control to warp on to the outside of the ARK, fusing itself to the Eclipse Cannon and navigating the colony towards Earth.

To stop the Biolizard, Sonic and Shadow both absorbed the power of the Chaos Emeralds, turning into Super Sonic and Super Shadow. Using their combined power, the two super-powered hedgehogs killed the creature and used Chaos Control to warp the ARK back into its original orbit, saving the Earth from total annihilation.

Appearance
The Biolizard appears as a giant lizard with a life support system on its back with tubes running down its neck to its head. The creature is documented as being 85 meters (280 feet) long, 30 meters (100 feet) wide, 19.5 meters (64 feet) at the tallest point on its back, and weighs 87.5 tons.

Biolizard

 * Resilience - The Biolizard has a thick, impenetrable hide. Sonic and Shadow's attacks were utterly useless against its skin.
 * Energy Attack - The Biolizard is capable of spitting large spheres of dark energy from its mouth to destroy enemies.
 * Eggs - The Biolizard was designed to be able to reproduce asexually, but the eggs it produced bore no offspring. When Shadow fought the creature, it produced dozens of small pink eggs that it could launch at Shadow. The eggs would explode on impact.
 * Chaos Control - The ability to manipulate time and space with Chaos energy. The Biolizard only had limited Chaos Control and only used it to teleport into the Eclipse Cannon core chamber and out again.

Finalhazard
"Finalhazard" is the name used to describe the Biolizard after it fused with the Eclipse Cannon. After this fusion, the creature manipulated the fall of the ARK, maintaining its collision course with Earth.
 * Eggs - The Finalhazard still produces eggs that it can launch at foes.
 * Lasers - Highly accurate laser beams could be fired from the creature's life-support module.

Weaknesses
The Biolizard's hide was impenetrable, but a weakness existed in the form of the very device that kept the creature alive. Shadow was able to grind along the cables running between the Biolizard's head and life-support system and strike the red core of the device, causing heavy damage.

When the Biolizard fused to the Eclipse Cannon, its vital functions were maintained by the weapon itself as its life-support pack had been heavily damaged by Shadow. After fusing to the cannon, the creature developed a number of large, swollen cysts all across its body that Sonic and Shadow were able to target in their Super forms. After the swellings were burst, the Finalhazard died and its control over the ARK was lifted, allowing Sonic and Shadow to use Chaos Control to warp the colony back to its original position.