Ancient Emerald Dragon

The dragon is aware of any creature that uses a psionic ability or communicates telepathically within 100 miles of it. As an action, the dragon can psionically observe a creature, object, or location it is familiar with within 100 miles. While observing a subject in this way, the dragon can see, hear, and communicate telepathically, but it is blind and deaf in regard to its physical senses and does not require food or water. The dragon can psionically observe a subject indefinitely and can end this effect and return to its own senses as an action.

The dragons spellcasting ability is Charisma (save DC 21). It can innately cast the following spells, requiring no material components.
- 3/Day Each: Confusion, Dominate Person, Hideous Laughter, Suggestion
- 1/Day: Irresistible Dance, Symbol

When the dragon fails a saving throw, it can choose to succeed instead. When it does, its eyes flash red as it goes into a fit of rage. Until the end of its next turn, it makes melee attacks with advantage against the creature that triggered the saving throw and with disadvantage against all other creatures.

The dragons psionic abilities are considered both magical and psionic.

Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 30 (4d10 + 8) piercing damage plus 9 (2d8) thunder damage.

Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 21 (3d8 + 8) slashing damage.

The dragon screams stripping flesh from bones and reason from minds in a 90-foot cone. Each creature in that area makes a DC 21 Constitution saving throw taking 88 (16d10) thunder damage on a failed save or half damage on a success. Creatures that fail this saving throw by 10 or more are also psionically confused until the end of their next turn.

The dragon attacks once with its bite and twice with its claws. In place of its bite it can use Psionic Wave.

When a creature the dragon can see damages the dragon, the dragon lashes out with a psionic screech. The attacker makes a DC 17 Wisdom saving throw, taking 27 (6d8) thunder damage on a failed save or half damage on a success. Confused creatures make this saving throw with disadvantage.

Each creature of the dragons choice that can hear it within 120 feet makes a DC 17 Wisdom saving throw. On a failure, a creature becomes psionically confused for 1 minute. A creature repeats the saving throw at the end of each of its turns, ending the effect on itself on a success.

The dragon psionically targets one creature within 60 feet. The target makes a DC 17 Wisdom saving throw, becoming confused on a failure. While confused in this way, the target regards their allies as traitorous enemies. When rolling to determine its actions, treat a roll of 1 to 4 as a result of 8. The target repeats the saving throw at the end of each of its turns, ending the effect on a success.

The dragon psionically rants nonsense at a creature that can hear it within 60 feet. The target makes a DC 18 Wisdom saving throw. On a failed save, the creature gains a randomly determined short-term mental stress effect or madness.

The dragon uses Psionic Wave.

Only one legendary action can be used at a time and only at the end of another creatures turn. It regains spent legendary actions at the start of its turn.