Darth Nihilus, Lord of Hunger

Lifelink, Deathtouch
When Darth Nihilus enters the battlefield, search your library for Darth Nihilus mask and exile it. For as long as
Darth Nihilus is on the field you may cast it
by paying life equal to its mana cost instead.
Darth Nihilus power is equal to the number
of creature cards in all graveyards.