Unearth
Sorcery
Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling 
Don't dig up the past if you're not prepared for the consequences.
Jeff Miracola
Double Masters 2022 (2X2)
• #357Rulings
If a card in a player's graveyard has {X} in its mana cost, X is considered to be 0.
(wotc • 2019-06-14)
Rulings
If a card in a player's graveyard has {X} in its mana cost, X is considered to be 0.
(wotc • 2019-06-14)