Source of Obscurity

Cumulative upkeep -- Discard a card.
(At the beginning of your upkeep, put an age counter
on this permanent, then sacrifice it unless you pay its
upkeep cost for each age counter on it.)
All players hands are revealed.
As long as it is your turn, treat your opponents
hand as if it was an additional hand you control,
and you may spend mana as though it were mana
of any color to cast those spells.