Oakhame Adversary

A green-hoser that hits green the hardest: the cost reduction only fires when the opponent is on green permanents, which means the card is priced to punish the mirror. Against another green deck it costs for a deathtouch body that turns every unblocked swing into a card, a rate that makes it a nightmare for a ground stall (deathtouch means the 2/3 trades up into anything, so opponents who want to keep it from connecting have to chump). Against a non-green opponent it reverts to a plain four-mana 2/3 that has to actually connect to earn its keep, which is the constraint doing its job: the card is a scalpel aimed at a specific archetype, not a generic value creature. This is a familiar design philosophy (the sideboard-hoser stapled to a maindeckable body) taken further than most, because the two halves reinforce each other: the same green-heavy boards that trigger the discount are the boards where a deathtouch attacker is hardest to profitably block. The card-draw trigger rewards the aggressor for pressing an advantage the discount already handed them, so a green mirror tips lopsided fast. It is the adversary cycle's clearest statement of intent: cheap and backbreaking against the color it names, honest and unremarkable against everyone else.