Cadstar, Author of the 369

Cadstar, Author of the 369 enters the battlefield tapped.
As long as Cadstar is tapped, you may cast spells as though they had flash.
Whenever Cadstar becomes untapped,
you draw a card and each opponent mills
one card.
"The three hundred and sixty nine, a gathering of stories, poems, thoughts, and letters. Bound within the body of the only one worthy of telling them or remembering them. Cursed with knowledge that can never be shared."