Just some silly backstory I thought up of where Kolossos originated.

Ivo Robotnik’s newest creation

A genetically enhanced hybrid born from DNA gathered from Sonic and DNA gathered from Knuckles, Robotnik sought to make an organism built with both speed and power to combat his greatest nemesis, Sonic, although both DNA were incompatible with each other, producing a mutated, violent hedgehog amalgamation, inheriting increased speed and immense strength.

Kolossos gained awareness while incubating inside in a specimen tank eventually escaping in Robotnik’s base, Metal Sonic attempted to take down Kolossos but was subdued by Kolossos’ superior strength, tearing the robots head from its body before engaging in a rampage through the base.