Thassa, God of the Sea is a mythic Legendary Enchantment Creature — God card from Theros (THS), collector number 66. Current market price: $5.52 (foil $11.53), TCGplayer market prices via Scryfall.
Indestructible As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.) At the beginning of your upkeep, scry 1. {1}{U}: Target creature you control can't be blocked this turn.