R'lyeh, the Sunken City

{t}: Add {u}{u}, {b}{b} or {u}{b}. Use this mana
only to cast blue or black creature spells.
{u/b}{u/b}{t}: Search your library for a Deep One,
reveal it, and put it in your hand. You lose
life equal to the card's converted mana cost. Shuffle your library afterwards. Use this ability only when you could cast a sorcery.