601.2a

To propose the casting of a spell, a player first moves that card (or that copy of a card) from where it is to the stack. It becomes the topmost object on the stack. It has all the characteristics of the card (or the copy of a card) associated with it, and that player becomes its controller. Any continuous effects that modify the characteristics of the spell as you start casting it begin as it is put on the stack (see rule 611.2f). The spell remains on the stack until it resolves, it’s countered, or a rule or effect moves it elsewhere.