Sifter Wurm
Creature — Wurm
Trample
When this creature enters, scry 3, then reveal the top card of your library. You gain life equal to that card's mana value.
Filip Burburan
Amonkhet Remastered (AKR)
• #219Rulings
For cards in your library with {X} in their mana costs, X is considered to be 0.
(wotc • 2020-11-10)
Once Sifter Wurm's triggered ability begins to resolve, no player may take other actions until it's done. Notably, opponents can't try to change your library after you scry but before you reveal the top card of your library.
(wotc • 2020-11-10)
Rulings
For cards in your library with {X} in their mana costs, X is considered to be 0.
(wotc • 2020-11-10)
Once Sifter Wurm's triggered ability begins to resolve, no player may take other actions until it's done. Notably, opponents can't try to change your library after you scry but before you reveal the top card of your library.
(wotc • 2020-11-10)