Fear When Squealing Devil enters, you may pay {X}. If you do, target creature gets +X/+0 until end of turn. When Squealing Devil enters, sacrifice it unless {B} was spent to cast it.
2006-05-01
For this creature to not be sacrificed, {B} must have been spent on the {1}{R} mana cost. It doesn't matter if {B} is spent on {X}.
2006-05-01
If this enters 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.
2006-05-01
You choose the value of X as Squealing Devil's ability resolves. X can be 0.