Iron Islands, Raider Homeland

Iron Islands, Raider Homelands enters the battlefield tapped.
{t}: Add {u} or {b} to your mana pool.
{u}{b}{t}: Target player puts the top five cards of
their library into their graveyard, then discards
two cards.
The islands are stern and stony places, scant of
comfort and bleak of prospect. Death is never far here,
and life is mean and meagre.