I feel like this has been asked before. It’s “DreamMaster”, isn’t it?
Chris here…
It may well have been - my memory’s not so good now that I’m getting old! 
Anyway - you’re correct, so it’s your turn! 
Take care…
Mumm-Ra was known for his disguises. Below I’ve written the ThunderCats whose forms he took over the course of the series. Just give me the episodes.
Jaga (more than once)
Lion-O
Panthro
Lynxo
Snarfer
I may have forgotten some… If I did, share them with us!
I think I’ve got them here.:
Jaga (more than once) “Catfight” and “Return to Thundera Parts 1 & 3”
Lion-O “Return of the Thundercubs”
Lynxo “The Thunderscope”
While I didn’t see any mention of Snarfer, Snarf Egbert was a disguise in “Chain of Loyalty”
Mumm-Ra created an evil clone of Panthro in "Splitting Image" with Hammerhand's ghost inside so I don't think that counts as a disguise.
You’ve got the first three for sure, Lady Ocelli, but Snarfer and Panthro are still up for grabs.
I don’t know the Snarfer one, but Mumm-Ra took other disguises. Some that I remember are:
- Sliky (“Garden of Delights”)
- King Arhur (“Excalibur”)
- Berbil (“The Mumm-Ra Berbil”)
- Dr Dometome (“Fond Memories”)
- Pumm-Ra (“Pumm-Ra”)
- That strange cat-like creature (“Runaways”)
- A dwarf (“All that Glitters”)
- A fly… don’t remember the episde
They’re not Thundercats. He said Thundercat disguises.
Oooopppsss… my and again; missed it somehow when I read it… it seems it’s not my week 
lol it’s not easy when you don’t have all the DVD’s
Okay, hint time. Here are some quotes.
Mumm-Ra (as Snarfer): Well, what are you waiting for, ThunderCats? Dig!
Mumm-Ra (as Panthro): Come on, [character who would give it away], old buddy! Pull yourself together.
That sounds like “Return of the ThunderCubs.”
ScrewLoose
Yes!
Nope. But close! He does want them to dig for treasure, but they’re not ThunderCubs. Yet.
Part ? of the 5-part Thundercubs. I remember the scene (I think), Lion-O uses the sword to see the treasure of ThunDera is inside a stalactite/stalacmite formation in the corner of a room.
Yep, you got it. It’s Part 3, but that doesn’t matter. Your turn!
mcss aerocoupe? It’s been a week. 
My bad. I actually forgot I had answered the previous question. Time to pull one out of thin air, I think I have it.
Name the episodes and character(s) where the Sword of Omens appears to destroy/kill/cause major harm to someone who has picked it up. There are at least 2.
Minor electrocution as self-defense (like Mumm-Ra as Pumm-Ra) does not count.
Hmmm… a hard one. I like it
I’ll give a clue this evening if no guesses by then.
Clue #1:
Neither character harmed were living, breathing, creatures at the time of of the incidents.
Grune is one, at the end of “The Ghost Warrior”, but I’m not sure of the other one just yet…