Siegehorn Ceratops is a rare Creature — Dinosaur card from Rivals of Ixalan Promos (PRIX), collector number 171p. Current market price: $3.20 (foil $2.66), 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.)