Loamrock Overwatch

Defender, flying
Whenever an opponent casts a creature spell,
choose one -
* Put a +1/+1 counter on Loamrock Overwatch.
* Untap Loamrock Overwatch.
As long as Loamrock Overwatch is untapped, creatures opponents control with power less than Loamrock Overwatch's power can't attack you or
a planeswalker you control.