- “Listen, just because we have a child together doesn't necessarily mean you know me, mmm'kay, princess?”— Dr. Cox
"My Catalyst" is the twelfth episode of Scrubs' third season, and is the first appearance of Michael J. Fox as Dr. Kevin Casey, a great doctor with OCD who arrives at the hospital and upstages everyone. Turk is pleased with his new time in surgery, until Dr. Casey beats his score. Dr. Cox is being upstaged by Dr. Casey, and J.D. thinks that Dr. Casey would make a better mentor.
Synopsis

J.D. asks Dr. Cox for some help with a patient, but is shocked when Dr. Cox tells J.D. to do it himself, and that he admitted he doesn't know much about the patient's illness. Turk is also shocked after surpassing Todd as the better surgeon after impressing Dr. Wen in surgery. Everyone though, is more interested in the fact that Dr. Kevin Casey will be arriving at the hospital for the next month; a terrific doctor with a case of OCD. Dr. Cox is surprised to meet him again, because he hasn't seen him since they were residents, and J.D. is interested to know what Dr. Cox was like as a resident. Dr. Kelso, however, seems more interested in the fact that birds are pooping on his car, and it turns out that Ted is secretly putting bird seed on his car.
Meanwhile, J.D. is watching Dr. Casey and is impressed with his medical knowledge and thinks it would be good if Dr. Casey was his mentor. Dr. Casey then also impresses Turk when he gives a diagnosis which Dr. Kelso couldn't do. Turk asks Dr. Wen if his time in surgery is better than Dr. Wen's time, and find out it is, and Turk looks forward to seeing Dr. Casey's time. Then Dr. Casey is challenged to a quiz with Dr. Cox, where residents try and ask them difficult questions to see who is the best doctor, both of them seem very good but J.D. asks a question that he knows Dr. Cox doesn't know, much to the embarrassment to Dr. Cox. Turk finally gets to watch Dr. Casey perform the surgery, and is amazed at the incredible speed he performs it, and watches a video of it over and over again in amazement. Dr. Casey seems out of everyone's league, Turk is attempting to get his time up but can't catch up, even when running through it in his head and Dr. Casey even upstages Dr. Cox at the cafeteria. J.D. however is upset when Dr. Casey comments that someone who has been in medicine for for as long as J.D. has shouldn't need a mentor.
J.D., Turk and Dr. Cox all decide to confront Dr. Casey over their separate issues, and J.D. eventually finds him madly washing his hands. An extremely frustrated Casey explains that even though he could have gone home hours ago and is desperate to do so, he can't because he can't stop washing his hands. He then apologizes to J.D., saying that he doesn't want to be someone who dumps his problems on other people. He then asks J.D. what he wants, and J.D. replies that he doesn't want anything and neither do Turk and Dr. Cox when they arrive and witness Casey's condition first hand, understanding that what makes him untouchable as a doctor also makes him completely cursed as a human being.
Recurring Themes
More: Fantasies • Flashbacks • J.D.'s girl names • Janitor's pranks and lies

Fantasies
- It's in the past, and a young Dr. Cox, with bleach-blonde hair and an earring walks over to some doctors and announces "Shut up, jackass! I rock!".
- Dr. Casey is practicing brain surgery on J.D., and prods certain areas of the brain for J.D. to speak gibberish, then French, then noises for a cow and a sheep.
Janitor story
The Janitor and his partner Randall are hired by Dr. Kelso to remove all of the garbage at Sacred Heart Hospital, but Dr. Kelso wonders where all the garbage has gone after he realizes Janitor and Randall never left Sacred Heart. Meanwhile, Ted, having been insulted by Dr. Casey, is convincing himself to jump off Sacred Heart and kill himself, when Dr. Kelso runs out onto the room blowing an airhorn which causes Ted to fall, but he lands in a pile of garbage.
J.D.'s Girls Names
- Beyoncé, used by Perry Cox.
- “Beyoncé, you could use a lot of help, but we all have to play the hand the big guy dealt us.”— Dr. Cox
- Britney, used by Perry Cox.
- Pink, used by Perry Cox.
- “Look, Pink, for the billionth time, no, I will not go out for a beer with you. Now repeat after me: Dr. Cox, you are not now, nor will you ever be, my mentor.”— Dr. Cox
Episode Running Gags
- One of Dr. Casey's quirks is that he must sign his name and say "Dr. Kevin Casey"
- Dr. Kelso uses an airhorn to scare birds off of the roof.
- Ted contemplates suicide.
- Dr. Cox decides to call J.D. by female pop stars' names.
Guest Stars

- Michael J. Fox as Dr. Kevin Casey
- Martin Klebba as Randall Winston (Custodian)
- Charles Chun as Dr. Phillip Wen
- Frank Encarnacao as Dr. Walter Mickhead
- John Maynard as Random Doctor
Music
♫ List of music featured in Scrubs
- "Good Thing" by David Boyles
- "Everything's Not Lost" by Coldplay
Quotes
- “Oh, that's fine. We were talking man talk...you know...”— J.D.
- “Really big trucks...”— Turk
- “Really big trucks...”— Turk
- “Solo-Flex...”
- “Have you seen these lately?”
- “Have you seen these lately?”
- “Sweat.”
- “Oh, that's fine. We were talking man talk...you know...”— J.D.
- “Who doesn't?”— Dr. Cox
- “Who doesn't?”— Dr. Cox
- “Everybody has their own burdens J.D., and I'm not gonna be one of those people that dump mine on somebody else.”— Dr. Casey
- “It's garbage.”— Janitor
- “It's garbage.”— Janitor
Trivia
- This was a 26 minute super sized episode (40 minutes including adverts). Re-airings cut out some content. However the original version is what's available on DVD and streaming
- Since Bill Lawrence had also created the show Spin City, he was friends with Michael J. Fox, which is how they secured the actor for a guest appearance.
- When Dr. Casey is signing his name several times, he begins signing on a yellow form and after the camera cuts, he finishes signing on a white form.
- The disease Dr. Casey diagnoses in the patient's room with Dr. Cox and Carla is Gaucher's disease, which is also a metabolic disease.
- J.D. actually helps the Janitor by not telling Dr. Kelso where the Janitor was taking the hospital's garbage, despite their feud.
- The coin that Dr. Casey gave to Turk for his dexterity exercise was a 2000 Sacagawea dollar. This coin is quite fitting because it was unique and uncommon to be used by the general population.
- When Jordan asks Dr. Casey if he's single, he replies that he is. In the previous scene, he was wearing a wedding ring.
Images