Ancient Copper Dragon

4/day (5/day in lair). If the ancient copper dragon fails a saving throw, it can choose to succeed instead.

The ancient copper dragon makes three Rend attacks. It can replace one attack with a use of (A) Slowing Breath or (B) Spellcasting to cast Mind Spike (level 5 version).

Melee Weapon Attack: +15 to hit, reach 15 ft.. Hit: 19 (2d10 + 8) slashing plus 9 (2d8) acid damage.

Recharge 6. Dexterity Saving Throw: DC 22, each creature in a 90-foot-long, 10-foot-wide Line.
Failure: 63 (14d8) acid damage.
Success: Half as much damage damage.

1 use per day. The ancient copper dragon casts one of the following spells, requiring no Material components and using Charisma as the spellcasting ability (spell save DC 21):
At Will: Detect Magic, Mind Spike (level 5 version), Minor Illusion, Shapechange (Beast or Humanoid form only, no Temporary Hit Points gained from the spell, and no Concentration or Temporary Hit Points required to maintain the spell)
1/Day Each: Greater Restoration, Major Image, Project Image

Constitution Saving Throw: DC 22, each creature in a 90-foot Cone.
Failure: The target can't take Reactions; its Speed is halved; and it can take either an action or a Bonus Action on its turn, not both. This effect lasts until the end of its next turn.

Charisma Saving Throw: DC 21, 1 creature the ancient copper dragon can see within 120 feet.
Failure: 31 (9d6) psychic damage. Until the end of its next turn, the target rolls 1d8 whenever it makes an ability check or attack roll and subtracts the number rolled from the D20 Test.
Failure or Success: The ancient copper dragon can't take this action again until the start of its next turn.

The ancient copper dragon uses Spellcasting to cast Mind Spike (level 5 version). The ancient copper dragon can't take this action again until the start of its next turn.

The ancient copper dragon moves up to half its Speed, and it makes one Rend attack.