Scourge of Fleets is a rare Creature — Kraken card from Duel Decks: Elspeth vs. Kiora (DDO), collector number 41. Current market price: $0.59, TCGplayer market prices via Scryfall.
When this creature enters, return each creature your opponents control with toughness X or less to its owner's hand, where X is the number of Islands you control.