Lulu, Stern Guardian

Stun counters usually arrive one at a time, as a punishing rider on a burn spell or a tap-down effect: a single skipped untap step, then the creature is free. What this card does is turn that one-shot tax into a recurring toll that scales. Once per combat, when an opponent commits to attacking you, you get to seed a stun counter onto one of the attackers, so a stun pile builds slowly across the game rather than all at once. The proliferate ability is where it compounds: every activation thickens every stun counter already in play, so a creature that came in with one counter walks away with two, three, four untap steps to burn off, sitting out combat while the pile grows. The design ties an inherently defensive punisher (attack me and your creature freezes) to an engine that rewards patience, since the tax accrues only as long as opponents keep testing your board. It leans on the quiet truth that proliferate does not care whose counters it touches, so the same activation that locks down an attacker can also feed your own planeswalkers, saga chapters, or +1/+1 lines. The 2/3 body is built to survive the early attacks that start the loop rather than to end games itself; the counters do the winning, and the body is just the seatbelt.