Inanna-Ishtar

Flying
{x}{u}{b}{r}, {t}: Gain control of target artifact with converted mana cost X or less. Untap it. Until
end of turn, that artifact's abilities cost {x} less to
activate, and you may spend mana as though it
were mana of any color to activate those abilities.
Sacrifice seven artifacts: Return Inanna-Ishtar
from your graveyard to the battlefield.