Kakashi, Glaring Dominance

Flying
When Kakashi, Glaring Dominance enters the battlefield, each player exiles the top X cards of his
or her library, where X is the amount of mana
spent to cast Kakashi.
Whenever Kakashi attacks, you may cast an instant or sorcery card exiled with it without paying its mana cost.

"We are Ninja. I will never forget."
-Kakashi Hatake