Mew

The genetic ancestor of all Pokemon. A floating pink cat-like creature. Mewtwo was created using DNA extracted from Mew's fossilized eyebrow. The leader of Team Rocket, known as Giovanni, was not satisfied with a mere clone of Mew, and instead insisted that a "superclone" be made by tinkering with Mew's DNA. It was the last mistake he ever made. Mew was retconned on September 28th, 2006, with the release of Pokemon Diamond and Pokemon Pearl in Japan, and with it the introduction of Arceus, the "God of all Pokemon." This created a conundrum of sorts, as it is explicitly stated that Mew's DNA can be found in the DNA of ALL POKEMON, yet Arceus was said to have existed before the universe itself began. Apparently, those continuity checkers at Nintendo didn't do such a great job, eh?