Brunhilda, Volcanic Queen

Pactbound (When you cast this spell, you may exile
a Pactholder creature you control. If you do, reduce
this card's mana cost by {x}, where {x} is the exiled
creature's converted mana cost. When this creature
dies, return the exiled creature to play.)
Flying, Haste
—
"I am Brunhilda, mistress of crimson, the inferno
clad, and the flame that shall guide your way!"