After having outwitted the Mane 6 in that Hedge Maze dilemma, Discord came to Ponyville to change it into the Chaos Capital of the World, as he was wreaking havoc with his chaos magic, every pony who saw him ran away in a panic, every pony except Dr. Scarabew Ballentine, she for one found this situation to be very fascinating, and actually began walking over towards Discord, as Discord kept spreading chaos he began laughing maniacally.
Then he heard a flat/dry-toned voice coming from behind him saying "Interesting, your inappropriate laughter may be a sign that you suffer from Hypomania".
Discord turned around to see a lone mare with a Light Beige Coat, Dark Red Hair, a Cutie Mark of a Fountain Pen & a Clipboard with Paper with an Ink Blot on it, and wearing a Light Gray cardigan sweater with large Navy colored buttons, and a set of half-cut reading glasses suspended from her neck by a long, thin chain, he then says to the mare "And just Who are You supposed to be? Another Pony Celestia sent to try and stop me?".
Dr. Ballentine replies with an emotionless expression on her face "My name is Dr. Scarabew Ballentine, and I'm actually the local Psychotherapist".
Discord replies "Oh, so I guess that makes you(he then miniaturizes himself small enough to stand on the tip of Dr. Ballentine's muzzle and continues to say) A Shrink?".
She simply replies "Your Immaturity may be a sign of Borderline Personality Disorder".
Discord's happy expression droops, then he poofs back to his normal size and says "Personality Disorder? Look Doc, I know exactly what MY Personality is, and it's not 'Disorder', I am Discord! The Lord of Chaos, The King of Disharmony, The Master of Everything Chaotic!".
Dr. Ballentine flatly responds "You also seem to be obsessed with yourself, a possible sign of Narcissistic Personality Disorder".
Discord makes a sour face that is like a cross between anger & confusion, he then turns to Dr. Ballentine and says "Will you stop doing That?! Why don't you just run away from me like every other pony in this boring old dump of a town?".
Dr. Ballentine replies in a monotone fashion "In all of my years of Mental Health Research & Therapy, I've never before met anyone as complex and intriguing as you, you may very well be the challenge I've long been looking for, if it's not too much trouble I would like to observe you, learn more about you, and ask you some questions, if I can come to understand you, and maybe solve whatever problems you may have, I may actually have done something truly worthy of my skills".
Discord is then intrigued by what Dr. Ballentine said and responds with "Observe Me? Hmmm, (With a devilish grin on his face he then says)This just got rather interesting, (he then bends down to make eye level contact with Dr. Ballentine and says)and I've never been one to turn down the oppertunity to give some pony a challenge, (he then stands up straight and says)Oh very well, (he then turns around and starts walking while saying)you can tag along just don't cause me too much trouble", with that Dr. Ballentine begins following Discord around as he continues to turn Ponyville into the Chaos Capital of the World.