Brineborn Cutthroat

Creature — Merfolk Pirate • Mana cost: {1}{U} • Foundations • Uncommon

Flash (You may cast this spell any time you could cast an instant.)
Whenever you cast a spell during an opponent's turn, put a +1/+1 counter on this creature.

"I always attack from where their spyglasses can't see."

Illustrated by Caio Monteiro.