Sylas, The Unshackled

When Sylas, The Unshackled enters the battlefield, you may copy a non-permanent spell
or ability with total converted mana cost 4 or less.
You may cast the copy without paying its mana
cost. You may cast spells this way only at times
you could cast a sorcery. You may only use this
ability once per turn.
"No more kings! No more queens! No more Mageseek-
rs it all ends now!"