Innate Spellcasting. The victillithid's innate spellcasting ability is Intelligence (spell save DC 16, +8 to hit with spell attacks). It can innately cast the following spells, requiring no components:

Whenever the Victillithid uses its Mind Blast, Psychic Field, or Psychic Ray, his Blasting Staff gains a single charge. Whenever the Victillithid makes an attack with the blasting staff he can expend that charge to deal an additional 2d8 psychic damage. The staff can only contain 1 charge.

Blasting Staff. Melee or Ranged Weapon Attack: +8 to hit, reach 5 ft. or range 90 ft., one creature. Hit: 4 (1d8) bludgeoning damage plus 9 (2d8) psychic damage in melee, or 9 (2d8) psychic damage when used at range.

When the Vivtillithid uses the charge contained in his staff, he gains a jolt of energy that increases his movement speed by 10 ft. until the end of his next turn.

Tentacles. Melee Weapon Attack: +8 to hit, reach 5 ft., one creature. Hit: 15 (2d10 + 4) psychic damage. If the target is Medium or smaller, it is grappled (escape DC 15) and must succeed on a DC 16 Intelligence Saving Throw or be stunned until this grapple ends.

Extract Brain. Melee Weapon Attack: +8 to hit, reach 5 ft., one incapacitated humanoid grappled by the Victillithid. Hit: 55 (10d10) piercing damage. If this damage reduces the target to 0 hit points, the Victillithid kills the target by extracting and devouring its brain.

Mind Blast (recharge 5 - 6). The Victillithid magically emits psychic energy in a 60-ft. cone. Each creature in that area must succeed on a DC 16 Intelligence saving throw or take 22 (4d8+4) psychic damage and be stunnned for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Psychic Field (Recharge 5 - 6). The Victillithid projects a 15 ft. radius field of energy centered on a point within 60 ft. Creatures within the field must make a DC 16 Intelligence saving throw or be stunned for 1 minute. Targets that fail the saving throw are pulled into the center of the field. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Psychic Ray (Recharge 5 - 6). The Victillithid projects a 20 ft. line of energy extending from a point within 60 ft. Creatures struck by the line must make a DC 16 Intelligence saving throw taking 40 (8d8+4) psychic damage on a failed save or half as much on a successful save. At the start of the Victillithid's next turn the line of energy explodes, all creatures within 5 ft. of the line must make a second DC 16 Intelligence saving throw taking an additional 22 (4d8+4) or half as much on a success.