The Energon Pub

They are both constantly thwarted by barely dressed musclemen with magic swords, and kinda wimpy villains, but what if they fought EACHOTHER? Who would win?

season 1 mumm-ra: Skeletor. that mumm-ra had that unexplained weakness to his own reflection, Skeletor would eventually blunder into it.

post season 1 mumm-ra... pretty easy to say Mumm-ra trumps the old skeletor in terms of magic powers. Both didn't need any item to cast their magic, but Mumm-ra eventually got himself an actual weapon ((the sword of plun-darr)) and it pretty much screwed the thundercats over.

I don't see anyone volunteering to transport these two evil bastards across the universe just for a little fight! They'd be nightmare passengers too. They'd insist that their pyramids / fortresses are transported too, for the power. They'd try to commandeer the star ships and use them to attack each other or anyone else they felt like attacking. The whole thing would be a sh!t show. Fight cancelled.