Mumm-Ra is perhaps one of the most famous villains to come out of the 80s and had a huge part in making ThunderCats the huge cult success that it has become.
Mumm-Ra had two forms. Most of the time he had a decrepit old body most resembling a mummy from ancient Egypt. However, when he uttered the famous lines, "Ancient Spirits of Evil, transform this decayed form to Mumm-Ra THE EVER LIVING!", he became a gigantic muscular villain that is easily one of the scariest we have ever seen!
Legends of the Multi-Universe (Porfirio's story)
Mumm-Ra wants to live forever. However, he is completely destroyed by Shenron's divine energy wave, reducing him to a pile of sand.