Indestructible (Effects that say "destroy" don't destroy that permanent. An indestructible creature can't be destroyed by damage.)
As long as your devotion to blue (Each in the mana costs of permanents you control counts towards your devotion to blue.) is less than five, Thassa isn't a creature.
At the beginning of your end step, exile up to one other target creature you control, then return that card to the battlefield under your control.
: Tap another target creature.