Invigorate

The free pump is a recurring green experiment, and the way this one settles its bill is the heart of the design: you do not pay zero, you pay three life, but it is the opponent's life total that climbs, not yours. That asymmetry is what makes a no-mana +4/+4 survivable to print. Handing an opponent three life is a real concession only against a long game; inside an explosive turn built to end before that number ever resolves into pressure, the gift is cosmetic. The Forest requirement is the color-pie anchor that keeps the alternative cost tethered to green decks rather than letting a free combat trick travel into any deck that wants it. What the card actually buys is information denial as much as raw stats: because no land taps to cast it, there is nothing on the board to read, so the ambush block, the surprise lethal through an open lane, or the save against removal all arrive with no mana telegraph for the opponent to play around. The plus-four is the headline; the absence of any signal that it is coming is what makes the trick land. It belongs to the family of green spells whose discount is denominated in a resource other than mana, and it is among the more aggressive members of that family precisely because the resource it spends is one you have already decided not to need.