Mindbreak Slash

As an additional cost to cast this spell, you may
exile an artifact card from your graveyard. If you
do, this spell has split second. (As long as this spell
is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Destroy target nonartifact creature. It can't be regenerated. Its controller discards cards equal to
that creature's mana value unless they have you
draw that many cards.