Armor Class 15
Hit Points 99 (18d8 + 18)
Speed 30 ft., fly 15 ft.
Saving Throws DEX +4, INT +7, WIS +6, CHA +6
Skills Arcana +7, Insight +6, Perception +6, Stealth +4
Damage Resistances psychic
Senses Darkvision 120 ft., passive Perception 16
Languages Deep Speech, Undercommon; telepathy 120 ft.
Challenge 7
Magic Resistance. The mind flayer has Advantage on saving throws against spells and other magical effects.
Tentacles. m +7, reach 5 ft. Hit: 22 (4d8 + 4) Psychic damage. If the target is a Medium or smaller creature, it has the Grappled condition (escape DC 14) from all the mind flayer's tentacles, and the target has the Stunned condition until the grapple ends.
Extract Brain. con DC 15, one creature that is Grappled by the mind flayer's Tentacles. 55 (10d10) Piercing damage. Half damage. If this damage reduces the target to 0 Hit Points, the mind flayer kills it and devours its brain.
Mind Blast (Recharge 5–6). int DC 15, each creature in a 60-foot Cone. 31 (6d8 + 4) Psychic damage, and the target has the Stunned condition until the end of the mind flayer's next turn. Half damage only.
Monster Manual (2024), p. 214