112.1 A spell is a card on the stack. As the first step of being cast (see rule 601, “Casting Spells”), the card becomes a spell and is moved to the top of the stack from the zone it was in, which is usually its owner’s hand. (See rule 405, “Stack.”) A spell remains on the stack as a spell until it resolves (see rule 608, “Resolving Spells and Abilities”), is countered (see rule 701.6), or otherwise leaves the stack. For more information, see section 6, “Spells, Abilities, and Effects.”
112.2 A spell’s owner is the same as the owner of the card that represents it, unless it’s a copy. In that case, the owner of the spell is the player under whose control it was put on the stack. A spell’s controller is, by default, the player who put it on the stack. Every spell has a controller.
112.2a Some effects instruct a player to create a copy of a card and say they may cast it. In that case, the owner of that copy is the player who is instructed to create it and given permission to cast it.
112.3 A noncopy spell’s characteristics are the same as those printed on its card, as modified by any continuous effects. See rule 613, “Interaction of Continuous Effects.”
112.4 If an effect of a resolving spell or ability changes any characteristics of a permanent spell, the effect continues to apply to the permanent when the spell resolves. See rule 400.7.