Bowser started life as an ordinary koopa living in the sewer, until one day a mysterious chemical got washed into the sewer. The chemical mutated bowser and turned him into something more than a normal koo...this can't be right, this is the origin story for the teenage mutant ninja turtles. Hmmmmm, ok I've got it this time, Bowser was a koopa who was bit by a radioactive dragon while on a high school field trip. He felt fine but the next day when he woke up he was able to br...dang it that's Spiderman's origin. Ok, um, this is my last try. Bowser was a koopa with a problem, he was addicted to fire flowers and the rush of power they gave him. He used that power to protect other koopa from danger, until one day he met an opponent he couldn't defeat. Having failed Bowser began to seek out more concentrated forms of fire flower, he eventually got to the point that he ingested pure fire seeds. The seeds took root in Bowser and gave him limitless power. He began to grow larger and spikes sprouted from his shell, as the transformation progressed he was filled with a burning rage and then fire erupted from his mouth. With his new power Bowser easily took power, dethroning the old king and enforcing his iron rule.