Thoroune, the Blinding Glory

When you spend mana produced from an
artifact to cast a spell, exile the top card of
your library. You may cast that card until the
end of your next turn. Spells exiled this way cost
X less to cast, where X is the amount of mana
from artifact sources you have spent this turn.
{b}{b}{r}{r}, {t}: Create a treasure token for each
land you own in exile.