Dryad's Favor

Dryad offering (You may cast this card any time
you could cast an instant by sacrificing a Dryad
permanent. If you do, the total cost to cast this card is
reduced by the sacrificed permanent’s mana cost.)
Choose target creature. If you spent {w} to cast
this spell, the chosen creature gains protection
from the color of your choice until end of turn.
Then put two +1/+1 counters on the chosen
creature if you spent {g} to cast this spell.