Triton Wavebreaker is a uncommon Enchantment Creature — Merfolk Wizard card from Modern Horizons 3 (MH3), collector number 74. Current market price: $0.23 (foil $0.30), TCGplayer market prices via Scryfall.
Bestow {1}{U} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached.) As long as this permanent is a creature, it has prowess. (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.) Enchanted creature gets +1/+1 and has prowess.