Biomass Mutation (C19 #187) MTG

Biomass Mutation is a rare printing from Commander 2019 (C19 #187), a Instant. Illustrated by Dan Murayama Scott.

Card text

Creatures you control have base power and toughness X/X until end of turn.

"A regression to ancient forms? A glimpse of future evolutions? Or a fleeting alteration of the present?"
—Vorel of the Hull Clade

As of 2026-10-19, Scryfall listed this printing at non-foil $0.23 (USD). Prices change constantly, so check the live price before buying.

January 24, 2013 — Choosing 0 as the value for X will likely cause creatures you control to become 0/0 and be put into the graveyard.
January 24, 2013 — Biomass Mutation overwrites any effects that set the power and/or toughness of a creature you control to a specific value. Effects that modify power and/or toughness but don't set them to a specific value (like the one created by Giant Growth), power/toughness changes from counters, and effects that switch a creature's power and toughness will continue to apply. For example, say you control a 1/1 creature that's getting +4/+2 from an Aura, has a +1/+1 counter on it, and is affected by an effect that switches its power and toughness. This creature is 4/6. If you cast Biomass Mutation with X equal to 4, the creature would become 7/9 (4/4, +4/+2 from the Aura, +1/+1 from the counter, then switch power and toughness).