Boom Scholar is a uncommon Creature — Goblin Advisor card from Aetherdrift (DFT), collector number 189. Current market price: $0.16 (foil $0.17), TCGplayer market prices via Scryfall.
Exhaust abilities of other permanents you control cost {2} less to activate. Exhaust — {4}{R}{G}: Creatures and Vehicles you control gain trample until end of turn. Put two +1/+1 counters on this creature. (Activate each exhaust ability only once.)