Star 879

Star 879 is a massive star that sent out the moon lord to do its bidding to conquer Terraria, and sience you defeated it's minion, it is angry, and wants revenge.

HP
Phase 1: 100,000

Phase 2: 999,999,999,999

Phase 1
Starstrike: stars that are fired out of the star wrath will strike on you.

Summon (passive): will summon 1 - 10 phantasm dragons.

Phase 2
Eye Beam: Lasers and cursed flames will come out of the eye.

Phantasmal Obliteration ray: A much bigger, much more powerful phantasmal deathray will come out, destroying blocks over time.

Spin: It will spin, dealing damage.

PowerSummon (passive): every summon has a chance to summon a dungeon gaurdian.

Other Things
"this is way to overpowered" you said, but wait, then fighting it, just before dying in the second phase, you get Armor of the Gods, the most powerful armor, with 999 maximum defence, only for Star 879's second form. also, you get Sword/Bow/Staff/Power orb of the Gods, each dealing 999 attack damage. you also get Wings of the Gods, giving you infinite flight.

Drops
1,000 - 1,000,000 Fallen stars

10 - 100 Star Shards

1 - 10 celestial sigil

1 eye of the forgotten

1 ancient scroll

Trivia
Star 879's real name is "God"

when going into the second form, the chat says: "foolish Terrarian! you thought it would be THAT easy? and you think you're good at this game!", and then there is a laugh.

when fighting this boss, the game is called "Star 879"