Varuna, Titan of Ocean's Ire

When Varuna enters the battlefield, sacrifice it
unless it escaped.
Whenever Varuna enters the battlefield or
attacks, target player puts the top ten cards of
their library into their graveyard.
Escape—{u}{u}{b}{b}, Exile five other cards from
your graveyard. (You may cast this card from your graveyard for its escape cost.)