Ammit, the Amber Cursed

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

Magic Resistance. The ammit has advantage on saving throws against spells and other magical effects, as well as effects that turn undead.

Mummified Core. The ammit has resistance to all damage until its mummified organs are destroyed. 

Multiattack. The ammit can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws or tail.

Bite. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 18 (2d10 + 7) piercing damage plus 5 (1d10) necrotic damage and the target is grappled and restrained. If a target is grappled and restrained, the ammit can instead swallow the target on its turn. The creature is blinded and restrained while inside of the ammit, and takes 16 (3d10) necrotic damage at the start of its turns. 

Claw. Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 14 (2d6 + 7) slashing damage.

Tail. Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 16 (2d8 + 7) bludgeoning damage.

Frightful Presence. Each creature of the ammit's choice that is within 120 feet of the ammit and aware of it must succeed on a DC 18 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to the ammit's Frightful Presence for the next 24 hours.

Dust Breath (Recharge 5–6). The ammit exhales necrotic dust in a 60-foot cone. Each creature in that cone must make a DC 20 Dexterity saving throw, taking 33 (6d10) fire damage and 33 (6d10) necrotic damage on a failed save, or half as much damage on a successful one.

Corrupting Presence. In response to a creature attempting to heal within 60 ft. of the ammit, they must succeed on a DC 16 Constitution save or take damage equal to the amount they would have healed. 

The ammit 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 ammit regains spent legendary actions at the start of its turn.

Tail Attack. The ammit makes a tail attack.

Dust Form (Costs 2 Actions). The ammit moves up to 30 ft. without provoking opportunity attacks. Any creature that the ammit moves by must succeed on a DC 15 Strength saving throw or be knocked prone.

Devour Soul (Costs 3 Actions). The ammit targets one creature it can see within 120 ft. The target must succeed on a DC 17 Wisdom saving throw. On a failure the target is reduced to zero hit points as the ammit absorbs its life force. The target has advantage on this saving throw if it is resistant to necrotic damage.