Squealing Devil | Magic: The Gathering
Formats Squealing Devil is Legal in
Official Oracle Text for Squealing Devil
When Squealing Devil enters the battlefield, you may pay . If you do, target creature gets +X/+0 until end of turn.
When Squealing Devil enters the battlefield, sacrifice it unless was spent to cast it.
Official Rulings for Squealing Devil
5/1/2006 : You choose the value of X as Squealing Devil's ability resolves. X can be 0.
5/1/2006 : If this enters the battlefield in a way other than announcing it as a spell, then the appropriate mana can't have been paid, and you'll have to sacrifice it.