Agonasaur Rex is a rare Creature — Dinosaur card from Aetherdrift Promos (PDFT), collector number 151p. Current market price: $0.65 (foil $0.51), TCGplayer market prices via Scryfall.
Trample Cycling {2}{G} ({2}{G}, Discard this card: Draw a card.) When you cycle this card, put two +1/+1 counters on up to one target creature or Vehicle. It gains trample and indestructible until end of turn.