dravun,betrayed demon

when dravun,betrayed demon comes into play exile target card from opponents hand and you get back target card from your exile pile.
{b}{b}any damage you do to your opponent double it for a turn
{b}{b}{x}sacrifice dravun, detrayed demon,for the rest of the game if you sacrifice a spell or a creature with converted mana cost {x} exile target creature or spell with converted mana cost {x}