Gravelgill Duo

Creature — Merfolk Rogue Warrior — {2}{U/B}

Whenever you cast a blue spell, this creature gets +1/+1 until end of turn.
Whenever you cast a black spell, this creature gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)

Rarity: common

EDHREC rank: 29976