Legality

Alchemy

Brawl

Commander

Duel

Gladiator

Historic

Legacy

Modern

Oathbreaker

Pauper

Pauper Commander

Penny

Pioneer

Standard

Timeless

Rulings
Nov 8, 2024

If a permanent on the battlefield has {X} in its mana cost, X is 0 for the purpose of determining its mana value.

Nov 8, 2024

If the target permanent is an illegal target by the time Feed the Swarm tries to resolve, the spell doesn't resolve. You don't lose any life. If the target is legal but not destroyed (most likely because it has indestructible), you do lose life.

Nov 8, 2024

The amount of life you lose is determined by the permanent's mana value as it last existed on the battlefield.