Norn's Inquisitor

The engine hides in the second line, and the trick is where the counter lands: whenever a permanent you control transforms into a Phyrexian, that permanent gets the +1/+1 counter, not this Knight. Incubate is the built-in fuel, because flipping an Incubator is exactly the transformation the trigger cares about. Pay the two mana to crack the token it made, and the fresh 0/0 Phyrexian arrives having already picked up its counter mid-flip, so a token that would settle as a 2/2 lands as a 3/3 instead. The 1/1 body is not the payoff; it is the ignition. What makes the design tidy is that the trigger is source-agnostic: it fires on any transform-into-Phyrexian on your side, so every incubate source and every Phyrexian double-faced card in the deck feeds it, not just the token this creature produces. That is the tell that it was built for a transform-density shell rather than a solo slot. The card is a keyword folded back on itself: incubate manufactures a Phyrexian, transforming into a Phyrexian buffs the thing that transformed, and both halves are printed on one two-drop so the loop closes without outside help. Strip away the transform permanents and the loop has nothing to bite: you get a fragile body that once turned an Incubator into a 3/3, and little else. The reward is entirely proportional to how much of your board is designed to flip.