Djinn Illuminatus

If you cast a spell that already has replicate while you have this creature on the battlefield, the spell will have two replicate abilities: one with a replicate cost as printed on it, and one with a replicate cost equal to its mana cost. (In this set, both costs are always the same.) You may use either ability, or both abilities, to replicate the spell.

If you cast an instant or sorcery spell that has in its mana cost, the value of X in the spell's replicate cost will be the same as the value of X you chose for its mana cost.