Omen of the Sea is a common Enchantment card from Theros Beyond Death (THB), collector number 58. Current market price: $0.25 (foil $0.49), TCGplayer market prices via Scryfall.
Flash (You may cast this spell any time you could cast an instant.) When this enchantment enters, scry 2, then draw a card. {2}{U}, Sacrifice this enchantment: Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)