Cosi's Trickster

A one-drop whose entire value is set by what the opponent is doing, not by anything you can do with it. The trigger keys off library shuffles, which means it preys on a structural habit: fetchlands cracked for color, tutors that reorder before they shuffle, scry-then-fail lines, any engine that rummages through its own deck as a cost of operating. Each shuffle drops a free +1/+1 counter, and against a deck that searches three or four times a game the growth compounds without you spending a card or a thought. The body asks nothing of you and rewards no sequencing decision; it simply taxes a behavior the opponent cannot easily stop. That is the unusual axis here. Most creatures grow through your own investment (mana sunk, spells cast, combat survived); this one grows through the opponent's compulsion to dig, which makes its clock entirely contingent on the list across the table. Face a deck that never shuffles and the trigger lies dormant, leaving a 1/1 with nothing to do; face a fetch-heavy or tutor-dense one and it snowballs into a real threat off no further input. The flavor reads clean: a trickster who profits from someone else's restless reordering of their own affairs. How high it climbs and how flat it stays are both decided before a single counter lands, and the card is honest about that asymmetry rather than hiding it.