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 - $3.00
Lightly Played - $2.75
Moderately Played - $2.25
Heavily Played - $1.75
Damaged - $1.50
Near Mint Non-English - $3.00
Lightly Played Non-English - $2.75
Moderately Played Non-English - $2.25
Heavily Played Non-English - $1.75
Damaged Non-English - $1.50