"Sword in a Hole": Lion-O orders the Sword of Owens to return to his hand, and it comes out of the black hole.
"The Telepathy Beam": With a little help from Lynx-O, Cheetara gets the confidence to fight against Vultureman's telepathy beam that been messing with her head, and proceeds to blow up the telepathy machine, attack the Sky Tomb, and save the Thundercats with the power of her mind.
Cheetara: I am Cheetara. In my heart, I know I'm the strongest of my kind. The pride of my people. I am unique in this universe, and I will not. BeDEFEATED!
Lion-O's anointment trials are all passed awesomely, but especially the Trial of Speed as Lion-O just barely manages to beat Cheetara in a race through sheer determination, refusing to give up even when he doesn't think he'll win.
Throughout the arc, Lion-O has to go unarmed for his trials, which makes all of his victories awesome - especially his big fight with Mumm-Ra.
At the end of the arc, Lion-O does the usual "Thundercats, Ho!" bit with the Sword of Omens - only this time now as the official Lord of the Thundercats!
The original series opening theme is still considered one of the eighties best.
Here's something you won't hear everyday, Snarfer is awesome! Near the end of the Mumm-Ra Lives arc, Snarfer came face to face with Alluro. Alluro tries his classic song and dance, which had almost beaten Panthro an episode earlier. But Snarfer throws off his magic in a snap!
Alluro: You don't stand a chance. (throws one of his magic sphere's towards Snarfer)
Snarfer: Snarfs never give in. Nope no sir. NEVER SAY DIE! (Snarfer head-butts the damn thing!)