Cadaverous Bloom

The engine that turned cards in hand into a resource you could spend twice. This converts each card you exile into two black or two green mana, which means your hand stops being a sequence of plays and becomes a fuel tank: the more you hold, the more mana you can dump in a single turn. Pair it with something that cashes that mana back into cards, and the loop closes. The classic build mated it with Squandered Resources to double the mana per land sacrifice and Prosperity to refill the hand it was busy emptying, generating an arbitrarily large pool to feed a single huge Drain Life. That deck, Pros-Bloom, is the reason this card is remembered: a true storm-shaped combo years before storm existed as a mechanic, built entirely out of the mana-conversion math this enchantment makes possible. The design tension is exactly that exile clause. Resources spent through Cadaverous Bloom are gone, not tapped and not sacrificed for later recursion, so the card forces a one-way commitment: you are trading future cards for present mana, and the whole archetype is the puzzle of spending that mana before the empty hand catches up with you. It is an early, unusually clean statement of the principle that a hand of cards is itself a mana source if you are willing to never get those cards back.