Blazing Shoal

Read the pitch clause carefully and notice what it does not say: exile a red card with mana value X from your hand rather than pay the spell's mana cost, with X set to whatever you pitched and nothing anywhere bounding that number. Exile a red card with mana value eight and you have bought a free +8/+0; pitch one for twenty and the buff scales just as freely, because the size of the pump tracks what leaves your hand, not what you spend. Note that the pitched card is exiled rather than discarded, which keeps it out of any graveyard recursion and matters only in that it makes the alternate cost a clean swap of cardboard for unbounded power. The +X/+0 itself reads as a forgettable one-shot pump, the kind of trick that wins a combat and gets sideboarded out. That uncapped number is what turned lethal once the spell met an infect creature: a single unblocked one-power attacker plus a free pump large enough to deal ten poison ends the game on the first or second turn, the whole package assembled at instant speed off one Arcane spell and a fat red card in hand. The deck that emerged was fast and consistent enough that the card was banned in Modern in 2011, part of the broader crackdown on the turn-two kills the format was built to discourage. What makes the design instructive is how little the printed text telegraphs the danger; the lethality lives entirely in a payment the card never bothers to bound, and the visible pump is just the lever that payment pulls.