Siegehorn Ceratops is a rare Creature — Dinosaur card from Rivals of Ixalan (RIX), collector number 171. Current market price: $0.53 (foil $1.90), TCGplayer market prices via Scryfall.
Enrage — Whenever this creature is dealt damage, put two +1/+1 counters on it. (It must survive the damage to get the counters.)