Cheapest priced copy (Teenage Mutant Ninja Turtles Eternal): $4.49 at Card Kingdom, near mint, their price list as of .
Mona Lisa, Ever Adaptable 
Legendary Creature — Lizard Mutant · 4/4 · Rare · Teenage Mutant Ninja Turtles Eternal · #126
Whenever a player casts a creature spell, you create a Mutagen token. (It's an artifact 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 · $4.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Teenage Mutant Ninja Turtles Eternal | 126 | Rare | $4.49 | — |
3 rulings from Wizards of the Coast
- 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."
- 27 January 2026Mona Lisa's ability resolves before the spell that caused it to trigger. It resolves even if that spell is countered or otherwise leaves the stack.
- 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.