Pioneer Masters

Brineborn Cutthroat

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."

Foundations Jumpstart

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 Brineborn Cutthroat.

Foundations

Jumpstart 2022

Flash
Whenever you cast a spell during an opponent's turn, put a +1/+1 counter on Brineborn Cutthroat.