Fancy Footwork

Untapping is the whole trick, and it turns what would be a forgettable two-body pump into a tempo instrument keyed entirely to the moment you fire it. Cast it before your own combat and it reads as a straightforward spread of +2/+2. Hold it, and on the opponent's turn the untap manufactures a blocker the board did not think existed: untap a creature you had tapped out for mana, throw it into the block step it had no business joining, then pump it past whatever the attacker committed. It can also crack your own attack open, freeing a creature to stay back or to push a second point of pressure. The pump fades at end of turn; the untap does not need a duration at all, since untapping is a one-time state change, so the creature is simply available the instant you resolve it and rolls into the next turn untouched. That mismatch (a permanent state change stapled to a temporary buff) is what makes it read as an action rather than a stat line. The Lesson subtype hooks it to learn, so a shell can fetch it from outside the deck rather than run it maindeck, delivering the effect on the exact turn a fight needs winning instead of rotting in an opening hand. Needing two creatures worth untapping to reach full value is the natural governor on an effect that would otherwise be an unconditional swing.