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.
1U: Target creature you control can't be blocked this turn.
Near Mint - £3.50
Lightly Played - £3.00
Moderately Played - £2.50
Heavily Played - £1.80
Damaged - £1.10
Near Mint Non English - £3.50
Lightly Played Non English - £3.00
Moderately Played Non English - £2.50
Heavily Played Non English - £1.80
Damaged Non English - £1.10