I like his hooded version, makes him look more devious. Actually now that I look closely at balgus’s avatar .. Mumm-ra kinda reminds me of a gorilla 
I liked the backstory they gave him in the comics.
Mumm-Ra being a former Thundercat, seems, I don’t know, the easy way out
Maybe he’s a mummified mutant vampire bat.
I agree.
The bat wings plus the ones on the hilt of the sword of plundarr for his action figure suggests he may be a bat.
I heard he was a retired unicorn keeper…
You would think they would have made him more snake-like since his crest is a snake not a bat.
The whole mummy thing screams ancient Egypt,as in the Exodus episode you clearly see the pyramids. But if we take a page from the Ancient Astronauts (my guilty pleasure) playbook, animal headed aliens supposedly came down to Earth, so why not colonize other worlds, and take the Egyptian threads along.
MGP
Maybe Mumm-Ra was the Egyptian God Amun-Ra and the other animals were part of the pantheon. Panthera could be Bastet! lol jk
But then we’d be going into Stargate territory again. lol
I don’t like the idea of Mumm-Ra being an ancient Thundarian. It feels like a cop out somehow. I much rather like the idea that he comes from a race of ancient bat mutants or something to that effect. Maybe their race was similar to the ancient Egyptians somehow in that they mummified their VIP dead for their everlasting journey to the beyond.
After the last episode I no longer think Mumm-Ra was a Thunderian. If he was he’d have to have been in charge for a LONG time. Which is possible, I suppose, but I think he either collected the animal slaves or created them (though I don’t like the idea of him creating them.)
Sticking to the Bad Ancient Astronaut theory 
MGP
I took another look at the picture and I can see how he was once a bat type Mutant;the nose is very bat-like.
Well Mumm-Ra could yet be human all be it with advanced technology and powers derived from the Ancient spirits of Evil. He could have started out on Earth, destroyed humanity and took what life was left and messed around with genetic engineering to create a host of slaves before setting off to get the stones of power.
Probably wrong, but that’s the fun in speculating about this kind of thing.