Jack-Jack Attack is a Pixar computer-animated short, which shows how Jack-Jack got his powers, something that had earlier only been implied by voice messages nearing the end of The Incredibles made by Kari McKeen.
This short film opens with Rick Dicker, a government agent assigned to aid "supers" in maintaining their anonymity, interviewing Kari McKeen about what happened when she was babysitting Jack-Jack Parr.
Kari attempts to reassure Mrs. Parr that she is more than capable of watching Jack-Jack. Suddenly, Mrs. Parr hangs up (due to missiles firing on her plane). Thinking nothing is wrong and they just got cut off, Kari plans to watch Jack-Jack play with various toys while listening to Mozart, purportedly to stimulate his mind. When she starts the music, Jack-Jack has an epiphany about his latent superpowers. While Kari's back is turned, he teleports himself to the kitchen counter, and then the fridge. Confused, Kari tries to call Mrs. Parr again to ask about Jack-Jack but nobody answers. As she leaves a message, Jack-Jack levitates and sits on the ceiling.
After getting Jack-Jack down, Kari places him in his playpen turned upside down, with a chair on top. She leaves another message for Mrs. Parr, frantically asking for advice on dealing with Jack-Jack's needs. Jack-Jack somehow escapes from his playpen and teleports to a high shelf. As he tumbles down, Kari rushes to catch him, but Jack-Jack phases through the floor (all except his diaper falls through because Kari caught it). Kari runs down to the basement, finding Jack-Jack floating around and phasing through the walls, eventually catching the baby when he tries to phase through the washing machine.
Now winded, Kari ties Jack-Jack to a rope attached to a weight to keep him stationary. She tries to calm him down by showing flashcards, which works at first. When Kari holds up a card with a campfire on it, Jack-Jack spontaneously bursts into fire, much to her horror. Kari manages to grab Jack-Jack with a pair of tongs and runs to the bathroom, where she douses him in the bathtub.
The next day, the Parrs' residence is a mess. Kari is on the verge of a breakdown and struggling to stay awake but has since mastered anticipating Jack-Jack's powers; while Jack-Jack, blissfully ignorant of the destruction, plays with his toys, she periodically uses the various tools at her disposal to counter his power surges (a fire extinguisher to put him out when he catches fire, a mirror to deflect his laser beams, etc.). The doorbell rings and Kari answers to find Syndrome (Who of all people, ends up saving Kari from going insane). She immediately assumes he is a replacement babysitter and gratefully agrees to leave Jack-Jack in his care. Syndrome feeds into the theory by hastily making up a story in which he falsely identifies the "S" on his suit as "Sitter" (since a "BS" for "Babysitter" was not appropriate for taking care of children).
Back in the present, Dicker is incredulous that Kari actually believed Syndrome, to which Kari defensively yells that she was not in a sound state of mind at the time due to sitting an "exploding" baby. Dicker then wonders if Kari has told anyone what happened. Kari states that she told her parents, but they thought she was simply joking. Kari then wishes she could forget the ordeal; to her fortune, and for the sake of the supers' anonymity, Dicker proceeds to erase Kari's memory of it.
- Among the toys that Jack-Jack plays with is the ball from Luxo, Jr..
- This is one of the only two times that all of Syndrome's face is visible to the audience. Throughout The Incredibles, both as a kid and as an adult, he is always wearing a mask except in his flashback after being disillusioned by Mr. Incredible.
- The music that Kari puts on for Jack-Jack is the third movement of Piano Sonata No. 11, KV 331, (Rondo Alla Turca) by Mozart.
- Other compositions by Mozart can be heard at various points in the short. When Kari is trying to catch Jack-Jack—who is floating around and passing through walls, floors, and other solid objects—Rondo from Eine Kleine Nachtmusik, KV 525, plays in the background. When Jack-Jack bursts into flames and runs around, Dies Irae from Requiem, KV 626, plays in the background. The latter music also plays during the credits of the short.
- This is the first movie-based Pixar short to be exclusively available on Blu-ray and DVD, not on VHS.
- 2006-Hugo Awards-Best Dramatic Presentation - Short Form-Nominated (Post-production)