Thassa, God of the Sea

• WOTC Official Reminder Textofficial rules
  Indestructible — Effects that say "destroy" don't destroy this permanent. A creature with indestructible can't be destroyed by damage.
• WOTC Official Reminder Textofficial rules
  Scry — Look at the top N cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.

• WWizards of the Coast2013-09-15
  Official Ruling
  You perform the actions stated on a card in sequence. For some spells and abilities, that means you'll scry last. For others, that means you'll scry and then perform other actions.
• WWizards of the Coast2013-09-15
  Official Ruling
  Mana symbols in the text boxes of permanents you control don't count toward your devotion to any color.
• WWizards of the Coast2013-09-15
  Official Ruling
  Hybrid mana symbols, monocolored hybrid mana symbols, and Phyrexian mana symbols do count toward your devotion to their color(s).
• WWizards of the Coast2013-09-15
  Official Ruling
  If an activated ability or triggered ability has an effect that depends on your devotion to a color, you count the number of mana symbols of that color among the mana costs of permanents you control as the ability resolves. The permanent with that ability will be counted if it's still on the battlefield at that time.
• WWizards of the Coast2013-09-15
  Official Ruling
  You choose how to order cards returned to your library after scrying no matter where you put them.
• WWizards of the Coast2013-09-15
  Official Ruling
  When you scry, you may put all the cards you look at back on top of your library, you may put all of those cards on the bottom of your library, or you may put some of those cards on top and the rest of them on the bottom.
• WWizards of the Coast2013-09-15
  Official Ruling
  Activating Thassa's last ability after the target creature has been blocked won't change or undo the block.
• WWizards of the Coast2013-09-15
  Official Ruling
  Scry appears on some spells and abilities with one or more targets. If all of the spell or ability's targets are illegal when it tries to resolve, it won't resolve and none of its effects will happen. You won't scry.
• WWizards of the Coast2013-09-15
  Official Ruling
  Numeric mana symbols (, , and so on) in mana costs of permanents you control don't count toward your devotion to any color.
• WWizards of the Coast2020-01-24
  Official Ruling
  Counters put on a God remain on it while it's not a creature, even if they have no effect.
• WWizards of the Coast2020-01-24
  Official Ruling
  The abilities of Gods function as long as they're on the battlefield, regardless of whether they're creatures.
• WWizards of the Coast2020-01-24
  Official Ruling
  As a God enters the battlefield, your devotion to its color will determine whether any replacement effects that affect creatures entering the battlefield apply to that God. Because replacement effects are considered before the God is on the battlefield, the mana symbols in its mana cost won't be counted when determining this.
• WWizards of the Coast2020-01-24
  Official Ruling
  The type-changing ability that can make a God not be a creature functions only on the battlefield. It's always a creature card in other zones, regardless of your devotion to its color. It's always a creature spell while it's on the stack.
• WWizards of the Coast2020-01-24
  Official Ruling
  If a God is attacking or blocking and it stops being a creature, it will be removed from combat. It won't rejoin combat if it resumes being a creature later during that combat.
• WWizards of the Coast2020-01-24
  Official Ruling
  If an effect causes a God to lose all abilities, its ability that causes it to stop being a creature still applies if appropriate.
• WWizards of the Coast2020-01-24
  Official Ruling
  If a God stops being a creature, it loses the type creature and the creature type God. It continues to be a legendary enchantment.
• WWizards of the Coast2020-01-24
  Official Ruling
  When a God enters the battlefield, your devotion to its color (including the mana symbols in the mana cost of the God itself) will determine if a creature entered the battlefield or not for abilities that trigger whenever a creature enters the battlefield.

Rulings via Scryfall