Target opponent loses 3 life.
CipherCipher appears on some instants and sorceries. It represents two abilities. The first is a spell ability that functions while the spell with cipher is on the stack. The second is a static ability that functions while the card with cipher is in the exile zone. “Cipher” means “If this spell is represented by a card, you may exile this card encoded on a creature you control” and “For as long as this card is encoded on that creature, that creature has ‘Whenever this creature deals combat damage to a player, you may copy the encoded card and you may cast the copy without paying its mana cost.’”
The term “encoded” describes the relationship between the card with cipher while in the exile zone and the creature chosen when the spell represented by that card resolves.
The card with cipher remains encoded on the chosen creature as long as the card with cipher remains exiled and the creature remains on the battlefield. The card remains encoded on that object even if it changes controller or stops being a creature, as long as it remains on the battlefield. (CR 702.99) (Then you may
exileTo exile an object, move it to the exile zone from wherever it is. See rule 406, “Exile.” (CR 701.13) this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may
castTo cast a spell is to take it from the zone it’s in (usually the hand), put it on the stack, and pay its costs, so that it will eventually resolve and have its effect. A player may cast a spell if they have priority. See rule 601, “Casting Spells.”
To cast a card is to cast it as a spell. (CR 701.5) a copy of the encoded card without paying its mana cost.)