Armor Class 16 (natural armor)
Hit Points 287 (23d12 + 138)
Speed 50 ft., swim 100 ft.
STR
27 (+8)
DEX
14 (+2)
CON
22 (+6)
INT
24 (+7)
WIS
18 (+4)
CHA
18 (+4)
Saving Throws Wis +10, Cha +10
Skills Arcana +13, Deception +10, Perception +10
Damage Resistances cold, psychic
Damage Immunities lightning, thunder
Condition Immunities charmed, frightened
Senses darkvision 120 ft., passive Perception 20
Languages Common, Giant, telepathy 120 ft.
Challenge 17 (18000 XP)
Proficiency Bonus +6
Amphibious.
Magic Resistance.
Multiattack.
Claw.
Tentacles.
Trident.
Psychic Wave (Recharge 6).
Spellcasting (Psionics).