When Lion-O is trying to reach Panthro in the Thundertank, he is animated with his sword. However, Pumm-ra had already the sword under his possession.
When Mumm-Ra shapeshifts into Pumm-Ra, we find that Mumm-Ra has to change to the Everliving before taking his Thunderian form.
Skill/Power First Use:
Eye of Thundera - Rendered useless when covered
Goof: In the night, Pumm-Ra disables the Thundertank to the point that when Lion-O tries to start it, it does not work. However, the Mutants somehow replace broken parts and get it running to later attack Lion-O.
This episode shows that the Sword of Omens does not always warn Lion-O when a fellow Thundercat is in danger. It did not warn him when Cheetara was captured by Mutants or when she was laying unconscious in front of Mumm-Ra in his pyramid. This is likely due to Cheetara never actually being in danger, seeing as the intent was always to return her unharmed.
The Thunderkittens went with Panthro, Tygra, and Cheetara to the Thundrilliam Fields. But when it became obvious that there was trouble back at Cats' Lair, the Thunderkittens were not with them and did not return home with the adult cats. They also did not return when Lion-O summoned the Eye of Thundera. They were not seen again until the very end of the episode as the Thundercats discussed everything that had just happened.
This is the first time Tygra, Panthro, Cheetara, and Snarf saw Mumm-Ra. Previously, Lion-O had been the only Thundercat to actually see him.
It is assumed that Third Earth is our Earth in the distant future. This is supported by Mumm-Ra's use of the word "Egyptian" in this episode. This is also consistent with the ruins that look like Ancient Egypt from The Unholy Alliance.
The sword chamber is locked with an ancient Egyptian tomb device. A rock in the wall to the right of the door must be turned in order for the door to open.
Jaga chose Tygra to be the head of the Thundercat council before his death, despite Lion-O being Lord.
Weapon First Use: Completely operation Cats' Lair
Lion-O: (to Pumm-Ra) The sword will not obey you, and without it, you are no match for me.
Jaga: Be not hasty in your decisions, Lion-O. Your instincts may be correct, but one does not make decisions by instinct alone. Let the facts weigh heavily on your mind and listen to your peers with caution.
Lion-O: Funny, she's never been late before.
Panthro: Cheetara late? That's like the sun forgetting to set.
Lion-O: I can't believe I misjudged that Pumm-Ra like I did.
Tygra: First impressions are often wrong. Trust is something that takes time to grow.
Lion-O: And I guess new friends are not as easily made as I thought.
Snarf: And friends like the Thundercats are forever.
All: Thundercats forever!