The creature Bio Rex was designed by the Keerlon Corporation. His creation is the result of genetic manipulation research that was outlawed on Earth centuries ago. He was created from the DNA of a fossilized dinosaur egg, but altered to have human-level intelligence and increased strength. Genetic design allowed for the development of higher brain functions equivalent to that of a human, but as a carnivorous predator, he is still as aggressive as Pico. Bio Rex was considered a breakthrough in genetic engineering and was entered into the F-Zero Grand Prix to garner publicity for their creation.
However, before he even got to race, he had to endure several press conferences, interviews, public appearances, alive under constant public scrutiny. Eventually, his patience reached a breaking point and his fiery temper caused some rather embarrassing bad press for the Keerlon Corporation. They distanced themselves from Bio Rex, who still intended to enter the Grand Prix. During his first year he, as a "new species", was determined to prove he was superior to human. However, the following year he entered mainly to satisfy his ravenous appetite for mammoth ribs.