Fassbender the Mind Flayer

Fassbender the Mind Flayer isn't a creature
unless you control three or more permanents you
don't own.
At the beginning of your end step, exile the
bottom card of each opponent's library face
down. For as long as those cards remain exiled
you may look at them, you may cast permanent
spells from among them, and you may spend
mana as though it were mana of any colour to
cast those spells.