Femto, God Hand

Femto, God Hand 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 color to cast those spells.