Jump-start

Jump-start is a keyword ability on instants and sorceries that allows the player to cast a spell from their graveyard for the additional cost of discarding a card. It was introduced in Guilds of Ravnica for the Izzet League of Ravnica. The spell card is exiled when it leaves the stack.

Description
Jump-start is similar to Flashback, allowing you to cast the same spell twice. This is especially functional in the late game, when the additional cost can be paid with excess lands or other less valuable cards. Casting a spell with jump-start follows all the normal timing rules, so sorceries with jump-start are still limited to your main phases. A spell with jump-start that was cast from your graveyard can still be countered, and if it has targets, it won't do anything if all its targets disappear or otherwise become illegal.

Rulings

 * You must still follow any timing restrictions and permissions, including those based on the card's type. For instance, you can cast a sorcery using jump-start only when you could normally cast a sorcery.
 * A spell cast using jump-start will always be exiled afterward, whether it resolves, is countered, or leaves the stack in some other way.
 * If an effect allows you to pay an alternative cost rather than a spell's mana cost, you may pay that alternative cost when you jump-start a spell. You'll still discard a card as an additional cost to cast it.
 * If a card with jump-start is put into your graveyard during your turn, you'll be able to cast it right away if it's legal to do so, before an opponent can take any actions.