Sifter Wurm
Creature — Wurm
Trample
When Sifter Wurm enters the battlefield, scry 3, then reveal the top card of your library. You gain life equal to that card's converted mana cost.
"Rhonas's monument belongs to the wurms now. Look elsewhere for refuge." —Arnun, vizier of the menagerie
7/7
Illustrated by
Hour of Devastation#135UncommonEnglishLegality
Rulings
Nov 10, 2020
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.
Nov 10, 2020
For cards in your library with 
in their mana costs, X is considered to be 0.