Mind Flayer Arcanist

The mind flayer has Advantage on saving throws against spells and other magical effects.

The mind flayer casts one of the following spells, requiring no spell components and using Intelligence as the spellcasting ability (spell save DC 17):

At will: Detect Magic, Detect Thoughts, Disguise Self, Mage Hand (the hand is Invisible)

1/day each: Clairvoyance, Dimension Door, Fireball (level 5 version), Lightning Bolt (level 5 version), Plane Shift (self only), Sending

The mind flayer casts Shield in response to that spell's trigger, using the same spellcasting ability as Spellcasting.

2/day: Shield

The mind flayer makes three Arcane Tentacles attacks.

Melee or Ranged Attack Roll: +9, reach 5 ft. or range 120 ft. Hit: 27 (4d10 + 5) Psychic damage, and the mind flayer can teleport the target up to 30 feet to an unoccupied space the mind flayer can see on a surface or liquid large enough to support the target. If this damage reduces the target to 0 Hit Points, the mind flayer kills it and magically devours its brain.

Intelligence Saving Throw: DC 17, each creature in a 40-foot Emanation originating from the mind flayer. Failure: 41 (8d8 + 5) Psychic damage, and the target has the Stunned condition until the end of the mind flayer's next turn. Success: Half damage only.