Rule 702.127a

Aftermath is an ability found on some split cards (see rule 709, “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.”