Hunter's Mark

A one-way bite spell built as a weapon against a single color. The base rate is quietly generous: green rarely gets to hand a creature +1/+1 at instant speed and then have it strike a creature or planeswalker for its full power, which converts a fair combat trick into a blowout when the buff pushes the attacker past its target. What sharpens it is the color-hate rider bolted on top. Point it at a blue permanent you don't control and the four-mana cost collapses to a single green, so it arrives cheaply into the teeth of the deck most likely to be holding up interaction. That is asymmetric design with a clear grudge: green striking at the one thing it has always been shorthand for hating, priced so the reward peaks only when the target is exactly what the card was pointed at. Notably, the counter-immunity is not tied to that mode at all; the spell simply can't be countered under any circumstances, which closes the loophole a permission deck would otherwise exploit by answering a cheap spell with a cheaper one. Against any other color the cost stays full and the effect is a slightly overpriced bite, which is the tradeoff that funds the anti-blue blowout. Pointed anti-blue tools reward reading the table, but few weave the color hate into the rate this cleanly while keeping the spell resilient no matter where it's aimed.