Jack-Jack acts like a typical baby. He laughs and giggles a lot but cries whenever he is disturbed. Like many infants, Jack-Jack's emotions are unpredictable; and since his powers are stimulated by them, being with Jack-Jack when the baby uses his powers becomes very difficult when attempting to pacify or restrain him. For instance, Jack-Jack loves Mozart's music to the point where he is stimulated by it. He also becomes enraged if he is given a cookie and is not allowed more. One of the few things that can calm him down is his mother and the rest of his family.
He is smart and intuitive for an infant as he recognized Syndrome as an enemy and identified the exploding plane as a danger. He was, in fact, the one who made his father accidentally kill Syndrome. He even recognized that the hypno mask Elastigirl was wearing made her evil, causing him to release her by removing it.
Jack-Jack is small, albeit at the average size for a baby as he stands 2'6". He has a single tuft of strawberry-blonde hair on his head and blue eyes. He also has two baby teeth on the bottom of his mouth. Although he is usually seen in a yellow onesie during his on-screen appearances in the film, he also has a red super suit with a black mask.
When he transforms into a little monster, Jack-Jack's skin turns red and gains sharp fangs and claws, that he can use to defend himself and look intimidating.
Mozart's music will trigger Jack-Jack into manifesting his powers, which Edna Mode uses to design a new suit that has sensors and a hand-held monitor, which alerts his family to upcoming use of his powers and allows them to counter them quickly. His powers and abilities are significant enough for his siblings to use him as a third member of a rescue team.
Powers and abilities
- Polymorphing: More than simply shapeshifting, Jack-Jack can manipulate his physical properties to achieve a variety of effects. So far he has displayed the following abilities:
- Metal Form: Jack-Jack is able to convert his body into heavy metal, giving him a much greater weight and density.
- Smoke Form: Jack-Jack can convert his body to smoke, making certain objects able to pass through him.
- Water Form: Jack-Jack can convert his body to water while maintaining his shape, but a simple touch can cause this form to pop like a water-filled balloon.
- Self-Combustion/Flame-Form: Jack-Jack alter his physiology to set himself aflame and can, to some limited extent, extend the fire around him. As his body remains solid, it seems that it is simply his skin that combusts. His flames can be doused with flame retardant foam, however. The Lego Incredibles video game also shows that Jack-Jack can create a beam of intense heat while in his flame form.
- Rubber Form: Jack-Jack can become soft and pliable with a visible sheen in order to fend off sharp attacks.
- Sparkler Form: Jack-Jack can convert his body into a mass of sparks while spinning in circles, which gives him a degree of control over electromagnetism (he was able to short out the power all across Edna's estate).
- Mimicry: Jack-Jack is able to mimic features of other people, such as their noses and hair, as well as mimic objects. This is first shown when he copies the facial features of Edna. It is unknown whether he can completely transform into another person.
- Monster Form: Jack-Jack is able to transform into a monster-like creature, with red skin, long nails, and sharp teeth. In this form, Jack-Jack has a much greater muscle mass, leading to bolstered strength and maneuverability. He's able to combine his Flame Form with his Monster form which further increases its offensive capabilities.
- Size Manipulation: Jack-Jack can increase his mass and physical size to break through small spaces or crash through walls. While in giant form, he is visibly chubbier all over. He can also change his overall size while remaining the same in physical shape when he shrinks.
- Molecular Vibration: He can vibrate at an extremely fast rate, dislodging himself out of the arms of enemies or to shake items off.
- Teleportation: He can disappear and mysteriously reappear in another location several feet away.
- Dimensional Travel: He can cross dimensional barriers (labeled 4 on Edna's monitor) and travel through. He can be heard and can hear others through this dimension.
- Intangibility: He can pass through solid objects including force fields with no visible injuries. This is usually accompanied by a blue electric effect.
- Wallcrawling: He can cling to, climb and sit on ceilings and vertical surfaces. This may or may not be tied to his levitation ability.
- Enhanced Bite/Matter Ingestion: He can chew and eat his way through the bars of a wooden crib.
- Telekinesis: He can move objects with his mind.
- Levitation: He can also lift himself into the air. It is unknown at this time if this power is self-propelled flight or part of his telekinesis, but he can manipulate the direction he wants to go as well as launch himself in the air to a tremendous height with just a sneeze.
- Laser Vision: He can fire needle thin green lasers (blue in Jack-Jack Attack) from his eyes. These are apparently light-based as they can be reflected easily by a hand mirror.
- Electrokinesis: He can generate electricity.
- Self-Duplication: He can create duplicates of himself.
- Enhanced Strength/Invulnerability: He is strong enough to physically fight a raccoon and throw lawn furniture. He does this without physical damage as stated by Bob Parr.
- Superhuman Speed: As shown in Auntie Edna, Jack-Jack can move at high speeds. However, he doesn't appear to be as fast as his brother, Dash.
Jack-Jack is first introduced being bathed in the sink by his mother, Helen as she talks on the phone to his father, Bob. He is later seen at dinner, with Helen trying to get him to eat his baby food by making funny faces, which he mimics. This also makes his older brother, Dash, feel weird. He laughs when his older siblings, Violet and Dash, get into a fight, enjoying the action and thinking they are playing.
In the montage scene, Jack-Jack is seen being taken care of by Bob, who has recently gained a large amount of confidence, after secretly taking a job on a remote island. He gives him a kiss on the cheek. Realizing that his dad has come to care for him more despite the latter's responsibilities, Jack-Jack giggles. Helen encourages Bob to take a turn feeding Jack-Jack, which he does. Later, Dash and Violet stow aboard a plane Helen had rented, and quickly called Violet's friend, Kari McKeen, to babysit him. The baby is seen playing with an orange ball in his high chair while Kari is talking to Helen on the phone.
He is not seen again until the end of the movie when Syndrome tries to kidnap him to raise him as a sidekick to get revenge on his family. However, thanks to Kari playing Mozart for him, he has learned of his powers and uses them (fire, steel, and demon forms) to escape from Syndrome who is flying up towards his hoverjet. As he is falling towards the ground, Helen catches him. He and the rest of the family are then saved from Syndrome's exploding plane thanks to Violet's force field. Jack-Jack then joins the others in laughter after Dash asks if they will have to move again. At the end of the movie, he is shown clapping for Dash from the bleachers during the track meet and is then shown to be ready to fight The Underminer, thereby setting up the events of the sequel.
In his own mini-movie, we see what happens to him and Kari while the rest of the family is fighting Syndrome. Kari decides to stimulate his cognitive abilities by giving him some educational toys and playing Mozart for him (as she has heard that Mozart makes babies smarter). Listening to the music, he has an epiphany about his powers.
Over the course of the night, he demonstrates many different powers, such as floating through the walls, catching on fire, and shooting laser beams out of his eyes, and Kari tries to keep him and the house in one piece. By morning, Kari has been up all night and figured out how to counter his powers. In her frazzled state of mind, she hands him over to Syndrome, whom she believes to be a replacement babysitter contacted by Helen.
In the sequel, the fight with The Underminer picks up where it left off. Jack-Jack is left in the care of his older siblings. Later, his family is moved into a motel and then into a fabulous new home after his mother gets a new job. While Helen is gone, Jack-Jack is tended to by Bob who does what he can to care for him and the baby enjoys his time with his father.
Jack Jack reveals to his father that, thanks to Kari, he has awakened at least seventeen of his powers when he fights off a raccoon. Bob is overjoyed to learn this but worried when he sees the rest of his son's many powers and decides to hide this from his family for a while as it could bring Helen home.
Eventually, Violet and Dash witness Jack-Jack's powers and they find out Bob is so sleep-deprived from trying to reign in Jack-Jack, so they call Lucius. At first, Lucius sees a normal infant but is surprised when his powers activate and describes Jack-Jack's abilities as "freaky" and advises Bob to get some outside help.
Bob leaves Jack-Jack in care of Edna, who refuses at first but her perspective changed when she is delighted at seeing his powers in action. When Bob picks Jack-Jack up, Edna reveals she upgraded Jack-Jack's suit to help Bob handle him and gives a demonstration. During the demo, Edna reveals that listening to Mozart's music caused Jack-Jack to unleash his powers. Edna describes him as a polymorph, explaining they have various abilities. When Jack-Jack sees a giant cookie, Bob declares that he must get cookies. Edna tells him that not only does he not need cookies, but he also should not use them with Jack-Jack no matter what he does: Any solution involving cookies will inevitably make him angry enough to not only use his Monster Transformation Power but his Self-Combustion power as well.
Shortly after Bob leaves upon being contacted by Evelyn Deavor that Helen is in trouble, Jack-Jack and his siblings are visited by the mind-controlled "wannabe" Supers. The children escape by the Incredibile (summoned by Dash) and make their way to the Devtech ship to search for their parents. They eventually find them as well as Lucius but are forced to take cover in Violet's force-field as their mind-controlled parents and "Uncle Lucius" attack them. Jack-Jack then floats through the force-field and up to his mother. Noticing the goggles, he uses his telekinesis ability to levitate the goggles off Helen, freeing her from Evelyn's control. Helen then removes the goggles from Bob and Lucius before proudly embracing her children. Jack-Jack uses his powers to assist in freeing the other hypnotized Supers from Evelyn's control as his mother is shocked to learn of them and Bob tells her they have to catch up later. Following Evelyn's arrest, Helen can't believe she missed watching her son's powers as Bob tells her that he has more. Later on, the Supers are made legal again.
After his family drops Tony Rydinger off at the movies, he officially joins them in fighting crime.
In this short, Bob takes Jack-Jack to Edna for her to study the powers he uses while Bob caught up on some much-needed rest. Taking Jack-Jack to Edna, she studies different superpowers he uses to impress her. When Edna becomes crowded by multiple Jack-Jack clones, Jack-Jack uses his monster form, combining it with his fire form. Later, Edna examines Jack-Jack for his powers he used and giving him a red suit. After studying, Edna then takes Jack-Jack to Bob as she explains to him that whenever she babysits Jack-Jack (unlike other babies), she does not charge him as Bob and Jack-Jack leave for home. At the end of the short, Edna notices Jack-Jack (presumably a clone of himself) next to her, as Edna runs off telling Bob that he forgot his baby.
- According to official sources, Jack-Jack is 1 year old, is 2'4" (0.71 m) and weighs 30 lbs (13 kg).
- In issue #0 of the comics, Jack-Jack 's full name is John Jackson Parr.
- As his name would suggest, he is a sort of Jack-of-All-Trades.
- Jack-Jack is not seen or mentioned in the video game and is the only non-playable character of the Parr family in the Disney Infinity games (he does, however, appear in early concept art for the game, indicating he was likely to appear as an NPC as part of the Incredibles playset before being dropped and is mentioned directly by Helen in her in-game quotes when she is left idle, wondering how Kari is handling him).
- In the comic series, Jack-Jack is the main character but his only used power is that of molecular transformation and appears limited to metal, fire, and monster forms. In the story arc "City of Incredibles", he plays a central role when he gets a cold and inadvertently spreads his transformation powers to others (including his own family), causing their own natural superpowers to be updated to their maximum potential.
- On art and merchandise for the first film, Jack-Jack wears his super suit, but in the film itself, he doesn't at all (except for the very end of the film).
- Jack-Jack has 17 known superpowers, potentially making him the most powerful Super in the Incredibles universe.
- However, he could have just general shape-shifting powers.
- Jack-Jack is the only member of the Parr family who is known for having many superpowers.
- It was planned for Jack-Jack to melt as part of his shape-shifting powers, but this idea wasn't used; it can be assumed that this was due to technical limitations at the time or the fact that it would have seemed too disturbing for younger viewers at the time.
- This limitation appears to have been corrected for the 2018 sequel as seen during his fight against the raccoon.
- Jack-Jack is the only member of his family who doesn't have an "i" emblem on his super-suit.
- Jack-Jack is responsible for both the simplest and the most advanced super-suit design Edna created: the first one for when he did not show any power and the second one for managing all of them.