Oni Island

{t}: Add {b}{b}{b} to your mana pool.
{b}, {t}: Target legendary Demon gets +1/+1
until end of turn.
At the beginning of each end step, roll a d20.
If the result is 5 or less, return Oni Island to its
owner's hand. If the result is 6-9, Oni Island
phases out. If the result is 10 or higher, an
opponent with the fewest cards in hand gains
control of Oni Island.