Cheapest priced copy (Teenage Mutant Ninja Turtles Eternal): $0.49 at Card Kingdom, near mint, their price list as of .
Shellshock 
Instant · Rare · Teenage Mutant Ninja Turtles Eternal · #25
For each opponent, choose up to one target creature that player controls. Shellshock deals X damage to each of those creatures. You create a Mutagen token for each creature dealt damage this way. (They're artifacts with "{1}, {T}, Sacrifice this token: Put a +1/+1 counter on target creature. Activate only as a sorcery.")
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $0.49 to $3.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Teenage Mutant Ninja Turtles Eternal | 25 | Rare | $0.49 | $3.99 |
2 rulings from Wizards of the Coast
- 27 January 2026Some spells and abilities that create Mutagen tokens require targets. If each target chosen is an illegal target as that spell or ability tries to resolve, it won't resolve. The Mutagen token won't be created.
- 27 January 2026Mutagen tokens are a kind of predefined token. Each one is a colorless artifact with the artifact subtype Mutagen and the ability "{1}, {T}, Sacrifice this token: Put a +1/+1 counter on target creature. Activate only as a sorcery."