Spell Copy

Spells and permanents that duplicate instant or sorcery spells on the stack, letting one card resolve twice or more. Includes one-shot copiers like Fork, Twincast, and Narset's Reversal; persistent copy engines like Swarm Intelligence, Thousand-Year Storm, and Lithoform Engine; and ETB copiers like Dualcaster Mage. Distinct from spellslinger.spell_payoff, which scales rewards off each cast without duplicating the spell, and from spellslinger.magecraft, whose triggers fire on casting or copying without themselves producing a copy. Excludes effects that copy creatures or create token copies of permanents, which belong with clone-style permanent duplication rather than stack copying.