Sith Betrayal

As an additional cost to cast this spell, sacrifice a creature you control.
Choose one. If you a control a commander when you cast this spell, you may choose both.
• Deal {x} damage to a creature your opponent controls, where {x} is the power of the creature you sacrificed.
• Draw {x} cards, where {x} is the mana cost of the card you sacrificed.
Ultimately, treachery is the way of the Sith.