Rocketeer Boostbuggy

A crewed Vehicle that funds its own attacks is the whole pitch here, and the crew cost is set as low as it will go: any single creature you can find turns the 3/2 on, and the Treasure lands the moment it declares as an attacker rather than on connection, so a chump block or a bounce spell does not cheat you out of the ramp. The loop wants a body cheap enough to leave the rest of your mana free, then compounds: swing, bank a Treasure, and spend that mana developing the hand that feeds the next crew.

The exhaust clause is the reason it does not go dead once the ground clogs. For three mana, once ever, it stops being a permanent that needs a crewer and becomes an artifact creature with a +1/+1 counter, a threat that attacks under its own power from then on. The trade is real: as a Vehicle it sits outside creature sweepers, but the exhausted form is a creature permanently, and exhaust makes the switch a one-way door rather than a repeatable toggle. You are converting dormant sweeper-dodging into standalone board presence you no longer rent a crewer for each turn. Two objects in one card built for Gruul shells that want mana and pressure from the same slot: a fragile early engine hungry for a wide board, then a hardened midgame body that has stopped needing one.