Colorstorm Stallion is a rare Creature — Elemental Horse card from Secrets of Strixhaven Promos (PSOS), collector number 180p. Current market price: $0.82 (foil $1.77), TCGplayer market prices via Scryfall.
Ward {1}, haste Opus — Whenever you cast an instant or sorcery spell, this creature gets +1/+1 until end of turn. If five or more mana was spent to cast that spell, create a token that's a copy of this creature.