Heknevem, Relic Miser

Haste
Whenever Heknevem, Relic Miser attacks, you
may pay {x}. If you do, gain control of target
artifact or Aura with converted mana cost X
until Heknevem leaves the battlefield. If you
gained control of an Aura this way, attach it to
Heknevem if able.
{2}{r}, Sacrifice an artifact or enchantment: Draw
a card, then discard a card.