Bio Rex as he appeared in F-Zero GX
|First Appeared||F-Zero X|
|Later Appeared|| F-Zero GX|
F-Zero Legend of Falcon
Bio Rex was all part of a splicing experiment which was banned on Earth ages ago and looked down upon by many, which is to say merging strands of human DNA with the mass amounts of leftover DNA contained in a fossilized dinosaur egg. This undertaking brought forth a bipedal reptilian creature with dominant humanistic attributes paired with the monstrous qualities of an originally mindless carnivore. Such an experiment was put to work by the mysterious Keerlon Corporation. Stationed on an unknown planet, they were able to accomplish the task of birthing a human/dinosaur hybrid which they rightfully named "Bio Rex"(which is evidentally what you get after bringing a t-rex back to life in a bio lab). Bio Rex possessed a greatly above-average intelligence given his prehistoric roots, amazing strength which stemmed from his tyrannosaur species, and laser-sharp focus and body control thanks to his natural carnivorous instincts. This eventually led him to the world of racing, to which the Keerlon Corporation backed him towards. Bio Rex agreed to this without hesitation so long as he remained under the care of his creators and was given the proper chance to show up the human race as insignificant to his mighty reptilian ancestors. With a drive similar to Billy's, Bio Rex remains a protagonist in the series due to his lack of affiliation with Black Shadow or Zoda(disregarding F-Zero Falcon Legend's canon).
 F-Zero X
In the second console-based installment of the F-Zero franchise, Bio Rex was introduced as a purebred beast with raw instincts and ambition. To win races at any cost and with a savage attitude to push him towards his goal every time. Even though this reason sounds pretty intense, Bio Rex is presented as rather modest and somewhat shy, almost appearing self-conscious of his rather monstrous appearance among the human populous.
 F-Zero GX
In the most recent console-based title, Bio Rex went the way of Samurai Goroh and became somewhat of a noticable bumbler, caring for nothing more than filling his own dinosaur-sized appetite at the end of each race rather than shaming every other race in the Universe in place of his own upon winning the F-Zero cup. This is made evident in a good deal of the answers he gives during F-Zero TV and the overall theme of his Master Class Video.
 F-Zero Climax
Due to the lack of an actual storyline, besides being based off of the finale to F-Zero Falcon Legend(character-wise), Bio Rex joins the roster again with a very tight grip and excellent body strength. As would go without saying, his speed was noticably shot due to this.
 F-Zero Legend of Falcon
In the anime adaptation, Bio Rex becomes one of the main right-hand men of the notorious Zoda(alongside Octoman). He's mainly seen as the muscle of Zoda's little traveling group while Octoman could essentially have filled in as the brains. All in all, he's mainly seen as a rather slapstick-like enemy in the series with no real threatening attributes other than being on the villian's side(and his appearance, of course).