Mirror of Twilight

Whenever you cast a Twili spell, you may pay {1}, if you do, create a 2/2 black Twili Shadow Beast creature token.
If you control ten or more Twili creatures, transform Mirror of Twilight.
"Only the true ruler of the Twili can destroy the Mirror of Twilight. Zant could only break the Mirror into shards... He couldn't utterly shatter it. That's proof of his false kingship." - Midna