Imskir Iron-Eater
Legendary Creature — Demon
Affinity for artifacts (This spell costs 
less to cast for each artifact you control.)
When Imskir enters, you draw X cards and you lose X life, where X is half the number of artifacts you control, rounded down.
, Sacrifice an artifact: Imskir deals damage equal to the sacrificed artifact's mana value to any target.
Tyler Walpole
Modern Horizons 3 (MH3)
• #374Rulings
Use the mana value of the sacrificed artifact as it last existed on the battlefield to determine how much damage is dealt.
(wotc • 2024-06-07)
The value of X is calculated only once, as Imskir Iron-Eater's triggered ability resolves.
(wotc • 2024-06-07)
If an artifact on the battlefield has {X} in its mana cost, X is 0 when determining its mana value.
(wotc • 2024-06-07)
Rulings
Use the mana value of the sacrificed artifact as it last existed on the battlefield to determine how much damage is dealt.
(wotc • 2024-06-07)
The value of X is calculated only once, as Imskir Iron-Eater's triggered ability resolves.
(wotc • 2024-06-07)
If an artifact on the battlefield has {X} in its mana cost, X is 0 when determining its mana value.
(wotc • 2024-06-07)