Ancient

Mind Weapons. The ancient's weapon attacks are magical. When the ancient hits with any weapon, the weapon deals an extra 4d8 psychic damage (included in the attack).

Innate Spellcasting. The ancient's spellcasting ability is Wisdom (spell save DC 17). The ancient can innately cast the following spells, requiring only verbal components:

At will: detect thoughts

1/day each: mind blank, dream

Magic Resistance. The ancient has advantage on saving throws against spells and other magical effects.

Multiattack. The ancient makes two melee attacks.

Mind Bite. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 7 (1d6 + 4) piercing damage plus 18 (4d8) psychic damage.

Healing Will (3/Day). The ancient touches another creature. The target magically regains 20 (4d8 + 2) hit points and is freed from any curse, disease, poison, blindness, or deafness.

Disguise. The ancient magically polymorphs into a humanoid or beast that has a challenge rating equal to or less than its own, or back into its true form. It reverts to its true form if it dies. Any equipment it is wearing or carrying is absorbed or borne by the new form (the ancient's choice).

In a new form, the ancient retains its game statistics and ability to speak, but its AC, movement modes, Strength, Dexterity, and special senses are replaced by those of the new form, and it gains any statistics and capabilities (except class features, legendary actions, and lair actions) that the new form has but that it lacks.