Merfolk Cave-Diver is a uncommon Creature — Merfolk Scout card from The Lost Caverns of Ixalan (LCI), collector number 65. Current market price: $0.19 (foil $0.28), TCGplayer market prices via Scryfall.
Whenever a creature you control explores, this creature gets +1/+0 until end of turn and can't be blocked this turn.