I believe that a skin of Ornn called Unicornn (get it Unicorn Ornn) would be a very good addition to the game, perhaps for April Fool 2019. The abilities would go as so.
Q (Volcanic Rupture):
The rock would be some sort of cloud thing and there would be a rainbow above and around it. The animation for it travelling underground could also be a rainbow line travelling underground.
W (Bellows Breath):
This one's pretty obvious, spewing rainbows and the brittle indicator would be a Halo above the enemies head.
E (Searing Charge):
Not sure about this one, it'd be pretty generic. Any help in the comments?
R (Call of the Forge God):
A GIANT UNICRON RUNNING!
If anyone has any other ideas please comment so I can add more to this post. Thanks!