The Last Day (S03E20)

With the Mutants and Lunataks out of the picture, the Ancient Spirits of Evil give Mumm-Ra a deadline until sunset to eliminate the Thundercats, demonstrating their seriousness by exiling Ma-Mutt. Mumm-Ra wreaks havoc across Third Earth, trapping Tygra, Cheetara, and Panthro in limbo, and entombing Lion-O alive. He then obliterates the Tower of Omens, narrowly allowing the Thunderkittens to escape before sending them to limbo as well. Snarf dives into the Book of Omens seeking a way to defeat Mumm-Ra. Jaga and the Thundercats in limbo enter the Eye of Thundera to free Lion-O. After his escape, Lion-O confronts Mumm-Ra at Cats Lair, learning from Snarf that Mumm-Ra's time is up. As sunset approaches, Mumm-Ra fails, leading to his banishment by the Ancient