Calen, Mechromancer

Whenever an artifact you control is put into a graveyard from the battlefield, you may have target creature get -X/-X until end of turn, where X is that artifact's converted mana cost.
{t}, Sacrifice an artifact you control: Return target artifact card from your graveyard to the battlefield with converted mana cost X or less, where X is 1 plus the sacrificed artifact's converted mana cost.