Cthulu, Titan of Tides Rage

When Cthulu enters the battlefield, sacrifice it
unless it escaped.
Whenever Cthulu enters the battlefield or attacks,
each player sends the top three cards from their library to their graveyard, then you may exile a
card from each of your opponents graveyards
Escape -- {u}{u}{b}{b}, Exile five other cards from
your graveyard. (You may cast this card from
your graveyard for its escape cost.)