Ancient Copper Dragon

The dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws.

The 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).

The dragon exhales gas in a 90-foot cone. Each creature in that area must succeed on a DC 22 Constitution saving throw. On a failed save, the creature can’t use reactions, its speed is halved, and it can’t make more than one attack on its turn. In addition, the creature can use either an action or a bonus action on its turn, but not both. These effects last for 1 minute. The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself with a successful save.

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.