Majin Vegeta was able to push himself to the very extreme limit of him being a super saiyan when he was under mind control from babidi and he was able to let go of everything and pushed harder than ever in the state of being pure evil and totally wicked only to reveal in the end that babidi was being fooled all the time, this is to that form where our proud prince let go of everything and gave us the very best battle in all of anime history after saiyan saga !