Retrace

Retrace is a keyword ability that allows the player to cast the card from their graveyard for its mana cost plus the additional cost of discarding a land. All spells with the ability Retrace are instants or sorceries; the one permanent is a planeswalker that grants Retrace to instants or sorceries via an emblem.

History
Retrace was introduced in Eventide. Maro has deemed it a 7 on the Storm Scale due to the repetition of play and developmental issues. While not necessarily related in origin, Jump-start corrects some of these issues by only letting it "flash back" once, allowing for a higher impact spells.

Much later, it reappeared on the planeswalker card Wrenn and Six and the sorcery card Throes of Chaos in Modern Horizons.

Rulings

 * Casting a card by using its retrace ability works just like casting any other card, with two exceptions: You're casting the card from your graveyard rather than your hand, and you must discard a land card in addition to any other costs.
 * A retrace card cast from your graveyard follows the normal timing rules for its card type.
 * To cast a retrace card from your graveyard, you must pay its mana cost as well as discard a land card.
 * When a retrace card you cast from your graveyard resolves or is countered, it's put back into your graveyard. You may use the retrace ability to cast it again.
 * If the active player casts a spell that has retrace, that player may cast that card again after it resolves, before another player can remove the card from the graveyard. The active player has priority after the spell resolves, so they can immediately cast a new spell. Since casting a card with retrace from the graveyard moves that card onto the stack, no one else would have the chance to affect it while it's still in the graveyard.

Trivia

 * Retrace was featured as rules card 1 of 8 in the Eventide set.
 * Flame Jab reuses the art of a Shadowmoor.