Lunar Mystic

The cleanest version of the spells-matter payoff: a four-mana body that turns every instant you cast into a draw, for a single extra mana per trigger. The crucial detail is that the trigger keys off casting, not resolution. Because it fires when you commit the spell to the stack rather than when the spell does anything useful, the draw is insulated from whatever happens to the instant itself: counter it, fizzle it on an illegal target, or cast it purely to feed the Wizard, and the draw still resolves, provided you can spare the extra mana. The trigger goes on the stack like any other, so opponents get their chance to respond and the payment-and-draw resolves in turn; what the casting clause protects is the connection between your spell and the card, not the timing. That same clause keeps the engine honest. Each instant only nets a card when you can afford the tax, so a deck built around this has to ration its mana between the spells it casts and the mana held back to convert them, turn after turn. The 2/2 is incidental; the card wants to sit behind cheap interaction and bury an opponent one cantrip-priced instant at a time. It descends from the blue payoffs that reward dense instant counts, the same impulse later stapled onto prowess and noncreature triggers, but here the reward is durable and repeatable. That durability is also its weakness: it asks you to keep a fragile four-drop alive long enough for the slow accumulation to matter.