Pirenin, Maviol Guardian

When Pirein enters the battlefield or is turned
face up, for each player that isn't your teammate, manifest the top card of their library.
You may spend mana as if it were mana of any
color to activate the abilities of face-down
creature spells.
Face down permanent cards you control have
morph. Their morph cost is equal to their
mana cost.
Morph {4}{w}{u}{g}