Dark Confidant
Creature — Human Wizard
At the beginning of your upkeep, reveal the top card of your library and put that card into your hand. You lose life equal to its mana value.
Greatness, at any cost.
Alex Brock
Ravnica Remastered (RVR)
• #323Rulings
If a card in a player's library has {X} in its mana cost, X is considered to be 0.
(wotc • 2020-08-07)
Rulings
If a card in a player's library has {X} in its mana cost, X is considered to be 0.
(wotc • 2020-08-07)