Hidden Volcano

A red source that spends its first turn coming in tapped and then, well after the board has developed, converts itself into a spell. The trade is deliberately back-loaded: the land does nothing but produce red until you can commit five mana on top of it and sacrifice the source you deployed a turn earlier, so the ability comes due exactly when a red deck can afford to give up a piece of its manabase for board presence. Those are the flood turns, the topdeck wars, the point where an extra threat off the top outweighs one more red mana. What makes the effect land is where discover sits: between cascade's cast-it-now and impulse draw's bank-it-for-later, letting you fire the hit immediately or tuck it into hand. Stapling that to a land is the real idea. You are not spending a nonland card to dig for threats; you are converting fixing that already earned its slot, so the discover costs nothing in deck space. The land carries its own conversion clause rather than a spell wearing a land's type line, and the sorcery-speed clock on the ability keeps it from becoming an instant-speed ambush: it is a resource you cash in on your own turn, once the game has stalled into the phase where a free spell wins races.