Tidal Colossus

{1}{u}, reveal Tidal Colossus from your hand: You
may play an additional Island this turn.
Tidal Colossus's power and toughness are both
equal to the number of Islands you control.
When Tidal Colossus enters the battlefield, if
you cast it from your hand, return all nonblue
and multicolored permanents to their owner's
hands.