Mumm-Ra, also known as Mumm-Ra the Ever Living, is the primary antagonist of the Thundercats franchise. He appears as a major player in the second Disney vs Non Disney Villains War.
Disney Vs Non Disney Villains - Part Two
Back from the Dead - Vs Scar
After the murder of his son, Pharaoh Rameses summons Mumm-Ra to wreak havoc upon Egypt's enemies. After the Pharaoh asks for a display of power, Mumm-Ra is grievously insulted. He immediately seeks out one of the war's faction leaders, Scar. Scar, cowardly as ever, sics his hyenas upon Mumm-Ra. Mumm-Ra effortlessly defeats them, forcing Scar into the fray himself. Mumm-Ra does get blinded by Scar, but recovers quickly. As Shenzi, Banzai, and Ed abandon Scar for his failure to defeat Mumm-Ra, the mummy knocks Scar off a cliff. Mumm-Ra delivers the final coup de gras, hypnotizing the hyenas while Scar is left to burn in the remnants of Pride Rock.
Aggressive Expansion
Mumm-Ra calls together his generals - Grune, Slithe, Kaynar, and Addicus - and readies himself for the war. He sends out Grune and Slithe to wipe out Mirage, one of the villains responsible for Mumm-Ra's initially being sealed away, but the two fail in their mission.
The Acolytes
Mumm-Ra, however, meets his match, if only briefly, in the Acolytes, a group of warriors trying to steal a crystal from the Book of Omens. Odin, the de facto leader of the faction, blasts Mumm-Ra away with a powerful spell. Threatened by the Dark Dragon, Mumm-Ra transforms into a more powerful form, Mumm-Ra the Everliving. This new form disarms Odin and trades blows with the Dark Dragon, eventually striking the latter with a backhanded spell. Hecate, however, calls all of the Acolytes together. With one massive attack, they overwhelm Mumm-Ra, who transforms into a bird and flies away.
Delegating
Mumm-Ra and Slithe send out Kaynar to track down Mirage. Kaynar finds Mirage in the Pridelands, though he gets into a scrap with Shere Khan. Shere Khan later turns traitor after Zira tries to kill him, alerting Mumm-Ra to Mirage's location. Mumm-Ra decides to enter the spirit realm and destroy Mirage once and for all. He orders Slithe to take out the rest of Mirage's allies; though the lizard man shows some impudence, he is eventually persuaded into the attack.
Defeat in the Spirit Realm
Mumm-Ra observes as Mirage and Zira travel in the spirit realm in hopes of defeating him. Mumm-Ra follows them into the realm and makes himself known. Zira attacks with wild slashes, slashes Mumm-Ra easily evades. Tired of toying with the lion, Mumm-Ra transforms into Mumm-Ra the Everliving once more. This new form knocks Zira off a cliff to her death. Mirage summons some fire cats to destroy Mumm-Ra, but he absorbs their energy. He then tries to annihilate Mirage, but she deflects the strike. Once again, Mirage's magic begins to banish Mumm-Ra. The mummy clings on, but soon discovers Scar, now existing in limbo in the spirit realm. The lion throws Mumm-Ra into oblivion. Mumm-Ra just manages to escape before the portal to the spirit realm explodes.
Humbled
Drained of energy, Mumm-Ra returns to his pyramid. Rameses, however, has returned. The pharaoh wants to know who was responsible for killing his son. Mumm-Ra is only too happy to reveal Queen Grimhilde as the killer.