Mona Lisa, Ever Adaptable {3}{G}
Legendary Creature — Lizard Mutant
GreenCommander: legal
Identity
Green
EDHREC rank
#13,427
Cheapest printing
US$3.19
TCGplayer
Printings
1
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.")
Every printing
highest TCGplayer market first; a card with only a thin single listing shows its low
In short
A Commander deck is a commander and 99 other cards, one copy of each (except basic lands), all inside the commander's colour identity. Paste a full list into the deck price calculator to price it and check it against the format.