Friendly Fire

Oracle Text

Target creature's controller reveals a card at random from their hand. Friendly Fire deals damage to that creature and that player equal to the revealed card's converted mana cost.

Card Rulings

11/24/2014 Cards that don’t have mana costs, such as land cards, have a converted mana cost of 0.
11/24/2014 If the card has in its mana cost, X is 0.