The Mutagen is doing the heavy lifting here, but TMT does not reward the patience the card demands. The 0/3 walls a Foot Ninja and little else, and the format's 2/3 and 3/2 commons climb past it by turn three. The counter then sits in the awkward middle: one mana at sorcery speed to grow a creature already on the board, in a medium-speed format where Sneak decks would rather deploy a fresh evasive threat than reinforce a stalled one.
The real home is GU, a core common color pair in this set, where the token padding the artifact count matters as much as the +1/+1 it banks. The 0/3 chump-and-bank line buys time for that deck's slower payoffs, and the artifact subtheme cares about a free token landing the turn the creature enters. Equipment decks running Bespoke Bō can turn the 0/3 into a real attacker once the counter lands, which is the one sequence that justifies the body at all. The punisher is Grounded for Life: any Commando caught tapped dies for one mana, and white drafters see that card constantly.
This is a P1P9 to P1P12 pick that sometimes wheels, maindecked only when the two-drop slot is bare and Mechanized Ninja Cavalry has dried up. Draftsim's 2/10 is right about the body and a little harsh on the token, which quietly feeds the artifact-count decks that care. But the ceiling stays low: the counter costs one mana to activate, yet the sorcery clause keeps it out of combat math, and with no common sacrifice outlet to redirect the Mutagen toward something better than a slow buff, the card never compounds past its first small advantage.
