Ancient Chameleon Dragon

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

Natural Camouflage. The dragon can cast Greater Invisibility at will, targeting only itself and requiring no components. 

Reflective Resistance. When the dragon is subjected to a damage type other than bludgeoning, piercing, or slashing, it may use its reaction to gain immunity to that damage type for the next minute. This trait can only be used once per minute.

Multiattack. The dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws. It can replace one of its claw attacks with a Tongue Whip if it does not have a creature restrained. 

Bite. Melee Weapon Attack: +17 to hit, reach 15 ft., one target. Hit: 21 (2d10 + 10) piercing damage.

Claw. Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 17 (2d6 + 10) slashing damage.

Tail. Melee Weapon Attack: +17 to hit, reach 20 ft., one target. Hit: 19 (2d8 + 10) bludgeoning damage.

Tongue Whip. Melee Weapon Attack: +17 to hit, reach 60 ft. one target. Hit. 23 (2d12+10) bludgeoning damage. On hit, target must make DC 25 Strength saving throw or be pulled to the dragon and become restrained. A creature may use one attack from their attack action to remake this saving throw, breaking the restrained condition on a success.

Frightful Presence. Each creature of the dragon's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 21 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 dragon's Frightful Presence for the next 24 hours.

Breath Weapons (Recharge 5–6). The dragon uses one of the following breath weapons.

Camo Breath. The dragon exhales an icy blast in a 90-foot cone. Each creature in that area must make a DC 24 Constitution or Dexterity saving throw (dragons choice), taking 67 (15d8) damage on a failure, and half on a success. The damage type can be whichever one the dragon chooses, aside from bludgeoning, piercing, or slashing damage. 

Paralyzing Breath. The dragon exhales paralyzing gas in a 90-foot cone. Each creature in that area must succeed on a DC 24 Wisdom saving throw or become charmed for 1 minute. While charmed in this way, the creature sees illusions that feel real to the creature. At the start of their turn, they must roll 1d4 to decide what they will do on their turn.

1. A creature uses their full movement speed and a Dash action to attempt to chase something only they can see in a random direction
2. The creature lies prone, staring up with awe at something above them that only they can see.
3. The creature will use its action to make a melee attack against the closest creature to them that they can see, driven blind with rage by visions only they can see.
4. The creature sees the chameleon dragon as something damaged that they must try and fix. If the creature has access to any features or spells that can heal another creature, they will use their action or bonus action to use a feature or spell at its base level on the dragon. If a creature does not have the capability to heal magically, they will attempt to get withing 5 feet of th dragon and make a DC 10 Medicine check. on a success, the dragon may roll 1 of its hit die, regaining hit points equal to the number rolled + its Constitution modifier. 

Reflective Scales. The dragon can use its action to take on the appearance of any Dragon, or return to its normal appearance. While in this form, it retains all of its normal features, but can mimic the appearance and voice of this dragon perfectly. A creature may make a DC 24 Insight check to realize that that the dragon is not what they say they are. 

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

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

Tail Attack. The dragon makes a tail attack.

Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 15 feet of the dragon must succeed on a DC 25 Dexterity saving throw or take 17 (2d6 + 10) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.

Instinctive Invisibility (Costs 3 Actions). The dragon uses its Natural Camoflage trait.