The line comes from Yu-Gi-Oh GX, the anime follow-up to the original Yu-Gi-Oh series, where Tyranno Hassleberry is a duelist who builds his deck around dinosaurs and embraces that identity completely. His declaration about having dino DNA captures his whole character in a few seconds, which is why fans clipped it and shared it as a standalone sound. It has since become a handy shorthand in edits for overconfidence, dinosaur jokes and duelling bravado, because the reference is clear even to viewers who only vaguely remember the show.