Nanoform Sentinel

Tapping is almost always a cost you pay reluctantly: the price of attacking, of turning a permanent sideways for mana, of paying into someone else's ability. This 3/2 flips that logic by turning its own tapping into a refund, untapping another permanent the moment it goes tapped itself. Attack with it and free a mana source before your second main phase; tap it to crew a Vehicle, convoke a spell, or pay any cost that asks it to turn sideways, and get an untap out of the deal. That reset only fires once per turn, and the restriction is what keeps the design from breaking: without it, any effect that repeatedly taps and untaps this creature would collapse into an arbitrary engine, so the untap pays out a single time no matter how often the tapping happens. It reads like vigilance pointed outward rather than inward, generating a small recurring tempo edge every turn it survives, and the trigger keys off the creature becoming tapped, so it rewards you however the tap happens—even when an opponent's effect is what taps it. The value was never in the stats; it is in that repeated untap, which asks you to keep a permanent worth resetting in play rather than treating the ability as free upside. Point it at nothing worth untapping and it is just a fragile blue beater.