It looks like green has itself a new combat trick which may be a staple in Innistrad, Standard, Modern, and maybe even Legacy decks. I'm not too sure. What I do know for certain is that it's going to find it's way into at least a couple of my casual decks here on this blog:
A persistent Giant Growth. Say it out loud and let it sink in. At the cost of 1 green mana at instant speed, this card is going to be huge in the Innistrad Draft format. If your opponent is playing green and if they have a single green mana source open, you're never going to feel comfortable whenever you attack or block. Morbid enablers just got another reason to be picked higher in each pack.
Whenever I see solid cards that deal with +1/+1 counters, my mind immediately goes to Proliferation Decks and cards like Triskelion, Pentavus, and Spike Weaver. Imagine a Blue/Green semi-aggro Proliferation Deck with a 2nd turn Thrummingbird, leading into a 3rd turn attack and pump. You could potentially have a 4th turn 5/5 flier ready to beat some more face. Of course, you would have to find a way to trigger morbid, but in Legacy, I'm sure it can't be too hard to figure out.