Arvin, Treetop Scout

Reach
Whenever a creature with flying an opponent controls attacks you or a planeswalker you control, Arvin, Treetop Scout deals 1 damage to that creature. If a creature dealt damage this way has power 4 or greater, you may pay {2}. If you do, that creature loses flying until end of turn.
"The predators of the skies will terrorize these woods no more."