17 (natural armor)
348 (24d20+96)
walk 30 ft., fly 60 ft. (hover)
CON +9, WIS +6
Stealth +5, Perception +11
Blindsight 120 ft. while the spider's eyes are closed, passive Perception 21
15
+5
If the spider is motionless, has its eyes and mouth closed, and has its legs wrapped around its body at the start of combat, it has advantage on its initiative roll. Moreover, if a creature hasn't observed the spider move or act, that creature must succeed on a DC 18 Intelligence (Investigation) check to discern that the spider is anything other than an asteroid.
If the spider fails a saving throw, it can choose to succeed instead.
The spider doesn't require air.
The spider makes two Web Strand attacks, uses Reel and makes two Bite attacks.
Meele Weapon Attack: +13 to hit, reach 10 feet, one target. Hit 21 (3d8 +8 ) piercing damage plus 10 (3d6) acid damage.
Ranged Weapon Attack: +13 to hit, reach 120 ft., one creature. Hit: The target is grappled (escape DC 18). The web strand can be attacked and destroyed (AC 12; 20 hit points; vulnerability to fire damage; immunity to bludgeoning, poison, and psychic damage). The spider can grapple up to six creatures at a time using its web strands.
The spider pulls each creature grappled by it up to 60 feet straight toward itself.
The spider weavers a magical web around a spelljamming ship it can see within 120 feet of itself. The web lasts for 1 minute and suppresses the magic of any spelljamming helm aboard the ship. Decks and other surfaces of the ship that aren't enclosed become difficult terrain until the effect ends. The web is impervious to damage but is destroyed by a successful casitng of dispel magic (DC 18).