and sorcery spells cost
less to cast.
Regler omkring kortet.304
A player who has priority may cast an instant card from his or her hand. Casting an instant as a spell uses the stack. (See rule 601, “Casting Spells.”)304.2
When an instant spell resolves, the actions stated in its rules text are followed. Then it’s put into its owner’s graveyard.304.3
Instant subtypes are always a single word and are listed after a long dash: “Instant — Arcane.” Each word after the dash is a separate subtype. The set of instant subtypes is the same as the set of sorcery subtypes; these subtypes are called spell types. Instants may have multiple subtypes. See rule 205.3k for the complete list of spell types.304.4
Instants can’t enter the battlefield. If an instant would enter the battlefield, it remains in its previous zone instead.304.5
If text states that a player may do something “any time he or she could cast an instant,” it means only that the player must have priority. The player doesn’t need to have an instant he or she could actually cast. Effects that would prevent that player from casting a spell or casting an instant don’t affect the player’s capability to perform that action (unless the action is actually casting a spell or casting an instant).