Improvise is a static ability that functions while the spell with improvise is on the stack. “Improvise” means “For each generic mana in this spell’s total cost, you may tap an untapped artifact you control rather than pay that mana.”
May 3, 2019 · War of the Spark
Aftermath is an ability found on some split cards (see rule 708, “Split Cards”). It represents three static abilities. “Aftermath” means “You may cast this half of this split card from your graveyard,” “This half of this split card can’t be cast from any zone other than a graveyard,” and “If this spell was cast from a graveyard, exile it instead of putting it anywhere else any time it would leave the stack.”
January 25, 2019 · Ravnica Allegiance
Aftermath is an ability found on some split cards (see rule 708, "Split Cards"). It represents three static abilities. "Aftermath" means "You may cast this half of this split card from your graveyard," "This half of this split card can't be cast from any zone other than a graveyard," and "If this spell was cast from a graveyard, exile it instead of putting it anywhere else any time it would leave the stack."
April 28, 2017 · Amonkhet
Aftermath is an ability found on some split cards (see rule 708, “Split Cards”). It represents three static abilities. “Aftermath” means “You may cast this half of this split card from your graveyard,” “This half of this split card can’t be cast from any zone other than a graveyard,” and “If this spell was cast from a graveyard, exile it instead of putting it anywhere else any time it would leave the stack.”