Counterbalance | Magic: The Gathering
Formats Counterbalance is Legal in
Official Oracle Text for Counterbalance
Official Rulings for Counterbalance
7/15/2006 : If an opponent casts half of a split card (for example, Hit), and you reveal a split card where half of it has the same converted mana cost (for example, Hit/Run or Stand/Deliver), Counterbalance will counter the spell.