Ancient Aharem {Revised}

 Legendary Resistance (3/Day). If the Aharem fails a saving throw, it can choose to succeed instead.

Non-auditory Predator. While the Aharem is not invisible and has opened it's eye's, it loses the ability of tremor sense, hearing, and touch in general. all Wisdom (Perception)  checks not using it's vision are at disadvantage and suffer a -10 penalty to their score.

Innate Invisibility.  Once per round of combat, the Aharem has the ability to turn itself invisible at will by closing it's mouth and covering it's eyes within said mouth. The Aharem after doing this becomes invisible as if a greater invisibility spell had been cast on it. Nothing about the Aharem's size or characteristics changes, besides the fact that it must now rely purely upon sound and it's tremor sense to locate and distinguish it's surroundings. The Aharem loses it's ability to see, use it's breath weapon or eye attack.

Magic Resistance. The Aharem's has advantage on saving throws against spells and other magical effects.

Magic Weapons. The Aharem's weapon attacks are magical.

Gaze of the Aharem. When a creature that can see the Aharem's eyes starts its turn within 160 feet of the Aharem, the Aharem can force it to make a DC 23 Wisdom Saving Throw or be stunned for six seconds. On the start of the creatures next turn, they must make a DC 23 Charisma Saving Throw or take 26d6 psychic damage. Note the Aharem does not have to be able to see the creature or creatures, but if both the Aharem and target have met each other's gaze then the effects happen.

Unless surprised, a creature can avert its eyes to avoid the saving throw at the start of its turn. If the creature does so, it can't see the Aharem until the start of its next turn, when it can avert its eyes again. If the creature looks at the Aharem in the meantime, it must immediately make the save.

 Regeneration. The Aharem regains 20 hit points at the start of his turn. If he takes lightning, fire or radiant damage, this trait doesn’t function at the start of his next turn. The Aharem dies only if he starts his turn with 0 hit points and doesn’t regenerate.

Claws of the Jabberwok Slayer. Shards of a Vorpal Sword once broken against the Aharem replace its claws. A successful DC 12 Intelligence (Arcana) or Wisdom (Perception) check identifies them as such. When the Aharem rolls a 20 on an attack roll with a claw, the target is decapitated. (At your option, the attack can instead deal an extra 6d8 slashing damage.) A target is immune to this effect if it is immune to slashing damage, has legendary actions, doesn’t have or need a head, or if you decide that the target is too large for its head to be cut off by Aharem claws. If removed, the shards lose their magical powers.

Multiattack. The Aharem makes either five melee attacks (one bite and 4 tendril attacks), (two tendril attacks and one breath weapon), or (two tendril attacks and one eye attack).

Tendrils. Melee Weapon Attack: +18 to hit, reach 15 ft., one target. Hit: 24 (3d8 + 12) slashing damage. On a critical hit refer to Claws of the Jabberwok Slayer. 

Bite. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 24 (4d6 + 12) piercing damage and the target must make a Constitution Saving Throw DC 17  or take 46(13d6) force damage.

 Glass Breath (Recharge 5–6). The Aharem exhales glass and flux in a 160-foot line, (15ft wide). Each creature in that area must make a DC 24 Dexterity saving throw, taking 45 (13d6) piercing and 45 (13d6) force damage on a failed save, or half as much damage on a successful one.

Gaze of the Aharem. When a creature meets the gaze of an Aharem's golden eyes, the creature must make a DC 23 Wisdom Saving Throw or be stunned for six seconds. On the start of the creatures next turn, they must make a DC 23 Charisma Saving Throw or take (91)26d6 psychic damage.

Unless surprised, a creature can avert its eyes to avoid the saving throw at the start of its turn. If the creature does so, it can't see the Aharem until the start of its next turn, when it can avert its eyes again. If the creature looks at the Aharem in the meantime, it must immediately make the save.

The Aharem can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The Aharem regains spent legendary actions at the start of its turn.

Tendril Attack. The Aharem makes one tendril attack.

Detect. The Aharem makes a Wisdom (Perception) check.

Bite Attack (Costs 2 Actions). The Aharem makes one bite attack.

Invisibility (Costs 3 Actions). The Aharem closes it's mouth and becomes invisible. refer to Innate Invisibility.