Inkfathom Divers is a common Creature — Merfolk Soldier card from Duel Decks: Merfolk vs. Goblins (DDT), collector number 8. Current market price: $0.22, TCGplayer market prices via Scryfall.
Islandwalk (This creature can't be blocked as long as defending player controls an Island.) When this creature enters, look at the top four cards of your library, then put them back in any order.