Mother Rabia

You know what's cool? Umbrum. Rabia's an umbrum too. Their mom, I think, but she hardly looks any different from the rest! Just a big blue cloud of smoke with scary glowing eyes. Personally, I think she deserves to look a lot cooler than that, so here's how I think she'd look if she were stuffed into a unicorn vessel like her son!

Some random ideas I had while vectoring her:
-ancient artifact cape that no light may pass through or escape from, may or may not be the Rainbow of Darkness made manifest
-rad shadow cape contains the shadows of all monsters from within and outside Equestria
-could totally be a future villain for Luster Dawn to fight
-might've had a fling with the original Grogar?