The Great Eye (CR 20)

A huge bulbous orb covered in rune carved chitinous plates with ten tentacles and a body covered in a multitude of eyes hovers menacingly before you. Where a mouth should be are jagged tusks and multiple gill flaps that open and close rhythmically as its singular central eye stares unblinking at you. As its four large tentacles writhe, its two smaller tentacles, each ending in three digit-like protrusions move with grace, gathering arcane energies that coalesce in a globe of flames about to be unleashed with devastating effect. 

XP 307,200

NE Huge aberration (aquatic)

Init +6; Senses darkvision 90 ft., low-light vision, all-seeing; Perception +41

DEFENSE

AC 30, touch 11, flat-footed 27 (+2 Dex, +1 dodge, +19 natural, –2 size)

hp 150 (20d8+60); aqueous regeneration, electricity healing

Fort +13, Ref +10, Will +18

Immune electricity; SR 21

Aura electricity (5 ft., 2d6 electricity)

OFFENSE

Speed 5 ft., fly 30 ft. (good), swim 30 ft.

Melee 4 tentacles +21 (1d8+6)

Space 15 ft.; Reach 15 ft.

Spell-Like Abilities (CL 20th; concentration +26)