Ovabeus, Astral Mage

When Ovabeus, Astral Mage enters the
battlefield it becomes day and if it is already day
it becomes night.
Whenever it becomes day or night draw a card.
{t}: creatures your opponent's control get -2/-2.
until end of turn. Activate this ability only if it is
day.
{t}: creatures you control get +2/+2 until
end of turn. Activate this ability only if it is night.