Soul Transmogrifier

Double Strike, Menace
Whenever Soul Transmogrifier kills a creature,
place a soul counter on it.
Sacrifice another non-demon creature: Search
your library for a Demon with converted mana
cost X and place it onto the battlefield under
your control, where X is the number of soul
counters of Soul Transmogrifier. You may
only activate this ability as a sorcery.