Invigorate

Instant

If you control a Forest, rather than pay this spell's mana cost, you may have an opponent gain 3 life. Target creature gets +4/+4 until end of turn.

First printed October 4, 1999 in Mercadian Masques

Legality

August 7, 2020
To determine the total cost of a spell, start with the mana cost or alternative cost you're paying (such as the alternative cost of Invigorate), add any cost increases, then apply any cost reductions. The mana value of the spell remains unchanged, no matter what the total cost to cast it was.
August 7, 2020
If an effect says that an opponent can't gain life, you can't have that player gain life to pay Invigorate's alternative cost. If an effect instead replaces life gain, such as that of Sulfuric Vortex, you may choose to pay the cost even though the cost's action is replaced with nothing.