Grask, Titan of Earth's Hold

When Grask enters the battlefield, sacrifice it unless
it escaped.
Whenever Grask enters the battlefield or attacks,
each player mills 1, then you may return a
permanent card with mana value 2 or less from a graveyard to the battlefield under your control.
Escape—{b}{b}{g}{g}, Exile five other cards from
your graveyard. (You may cast this card from your graveyard for its escape cost.)