Magic Resistance. The Aberrant Mind flayer has advantage on saving throws against spells and other magical effects.

Regeneration. The Aberrant Mind flayer regains 10 hit points at the start of its turn. If the Mind flayer takes acid or fire damage, this trait doesn't function at the start of the Mind flayer's next turn. The Aberrant mind flayer dies only if it starts its turn with 0 hit points and doesn't regenerate.

Innate Spellcasting. The aberrant mind flayer's innate spellcasting ability is Intelligence (spell save DC 15, +6 to hit with spell attacks). The aberrant mind flayer can innately cast the following spells with no material components

Cantrips (at will): detect thoughts

Multiattack. The aberrant mind flayer makes one attack with its tentacles and one with its claws, or two with its claws.

Tentacles. Melee Weapon Attack: +6 to hit, reach 5 ft., 1 target. Hit: 15 (2d10 + 4) Piercing damage. If the target is Medium or smaller, it must make a DC 13 Constitution saving throw or take 5 (2d4) poison damage.

Claws. Melee Weapon Attack: +6 to hit, reach 5 ft., 1 target. Hit: 13 (2d8 + 4) Piercing damage.