Ancient Spirits of Evil, transform this decayed form to Mumm-Ra, the ever-living!! Since the ThunderCats had their original series in the 1980s, Mumm-Ra has been amongst the scariest of all cartoon characters. But this latest version on Cartoon Network truly proves the villain is ever-living! Completely reborn along with the rest of the saga, Mumm-Ra makes his true return in August 26th’s episode, Journey to the Tower of Omens. Lion-O and the rest of the ThunderCats must pass a series of obstacles to reach the Book of Omens. When Mumm-Ra rises to challenge them, it’s up to Lion-O to save the rest and secure the Stones of Power.