MAGIC: THE GATHERING
If you control a Forest, you may have an opponent gain 3 life rather than pay Invigorate's mana cost.
Target creature gets +4/+4 until end of turn.
There are a few strategies that Invigorate works very well with, all of which don't mind if your opponent gains a little bit of life. Legacy Infect is okay with the opponent gaining life because it wins through ten poison counters. There is also a Legacy underdog deck, The Cure, that uses the life gain to buff up Kavu Predators and drain extra life with False Cure.