Mono Blue

At the beginning of your upkeep, look at the top card of your library. You may reveal that card. If an instant or sorcery card is revealed this way, transform this creature.

Target creature you control gets +0/+3 and gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

{T}, Pay 1 life, Sacrifice this land: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

({T}: Add {U}.)

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)

Counter target spell unless its controller pays {X}.

Counter target spell unless its controller pays {3}.

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Draw a card.

Flying

{7}{U}: Adapt 4. This ability costs {1} less to activate for each instant and sorcery card in your graveyard. (If this creature has no +1/+1 counters on it, put four +1/+1 counters on it.)

Draw a card. Scry 2.

Look at the top two cards of your library. Put one of them into your hand and the other on the bottom of your library.

Flash

When this creature enters, target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

Counter target noncreature spell unless its controller pays {2}.

Flying

This creature gets +1/+0 for each basic Island you control.

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.