Canopy Ambusher

Reach
When Canopy Ambusher enters the battlefield,
if its stalk cost was paid, it gains first strike until
end of turn.
Stalk {1}{g}{g} (At the end of each block step, if there
is an unblocked creature attacking you, you may cast
this card for its stalk cost. If you do, choose an
unblocked creature attacking you. This creature blocks
that creature.)