Biolizard

The ARK monster was a gigantic Lizard-like creature that guarded the shrine room aboard the Space Colony ARK. It is assumed that it guarded the shrine room for fifty years until 3236, when Dr. Eggman released Shadow the Hedgehog from stasis and used the ARK in his attempts at world domination. After Shadow turned traitor and fought alongside Eggman's arch-enemy Sonic the Hedgehog, the monster used Chaos Control and pulled the ARK towards Mobius by fusing itself with the Eclipse Cannon, only to be stopped and, presumably, destroyed by the combined efforts of Super Sonic and Super Shadow. (SU: #2)


 * The beast that guarded the shrine room with the emeralds was known as the Biolizard, a prototype of the ultimate life form, shown in Sonic Adventure 2, but since this was never stated in the comics it is not considered canon by this site's canon policy.