The List

Eye of the Storm

Whenever a player casts an instant or sorcery card, exile it. Then that player copies each instant or sorcery card exiled with Eye of the Storm. For each copy, the player may cast the copy without paying its mana cost.

Ravnica: City of Guilds

Whenever a player plays an instant or sorcery card, remove it from the game. Then that player copies each instant or sorcery card removed from the game with Eye of the Storm. For each copy, the player may play the copy without paying its mana cost.