Darith Kal, Skyship Salvager

Whenever a nontoken artifact card is put into a graveyard from anywhere, you may pay {1}. If you
do, create a treasure token.
Sacrifice a treasure: Darith Kal, Skyship Salvager
deals 1 damage to any target.
Sacrifice four treasures: return target artifact card
from a graveyard to the battlefield tapped under
your control.