Kid Loki

A one-mana lord whose protection is transient by design: the hexproof clause covers any creature you've grown with a counter this turn, and it lapses when the turn ends. That reset is the whole point. Rather than charging a static tax for a permanent shield, the card gates protection behind the act of moving counters right now, which turns counter placement into a defensive tempo tool rather than a one-time buff. Because the window is per-turn, the interesting play is instant-speed: hold a proliferate or a cheap counter-adder for the opponent's turn and you re-arm the shield exactly when removal is coming, then let it lapse and refresh it again next cycle. The clock and the coverage are yours to manage turn by turn. Kid Loki also feeds itself: the second-card trigger grows him whenever you draw your second card in a turn, and because that counter lands this turn, he hands himself hexproof for the turn he grows. The two halves lock together without any external engine, unusual for a body that begins so small for a single blue. What it asks of a builder is fluency with timing rather than raw counter volume: knowing which turn to spend a counter on which creature, and reserving the effect for the moment protection actually matters. The hexproof is the payoff, the draw trigger is the fuel, and the turn boundary is the constraint that keeps the shield from ever calcifying into permanence.