|“||I am "Wonder of U", and the "flow" is always a calamity.||”|
—Wonder of U, JJL Chapter 99
Wonder of U has two forms, its main stand form and its disguise of Satoru Akefu, the TG University Head Doctor. As Satoru, Wonder of U appears as an 89 year old man, stooped and walking with a cane. He wears a black bowler hat and coat, gloves, and a scarf. His coat features buttons that resemble small suns. Usually, the doctor is only seen from behind, but when his face is revealed, he is shown to be an old man with a monocle, braided hair, and a series of spikes surrounding his mouth. In its human form, Wonder of U is visible to non-stand users, but it is unknown what they see when the stand teleports between locations or assumes its non-human form.
In it's stand form, Wonder of U stands upright and Akefu's human face is replaced by a mechanical head which resembles a radio microphone or a machine. Its eyes are shaped like suns, similar to the coat buttons. Underneath its clothing, Wonder of U has a slim, articulated mechanical body with a pair of blades on its arms.
Those who commit an act of "Pursuit" against the stand will suffer from "The Flow of Calamity." Anyone affected by the flow of calamity will be subject to a series of incidents with the intent to kill or disable that person. In the case of multiple pursuers, whoever is the most recent or active in pursuing Wonder of U, or Tooru himself, becomes the priority target. After the first person dies from a calamity, the ability moves on to the next target, creating a stacking effect. Only the highest priority target will be affected by the ability at any given time.
The range of the ability is unclear, but it appears to be infinite as long as the victim retains the intent to pursue. The stand can also phase through walls and hover in the air. It also seems to be able to teleport at will, as it completely disappeared when being pursued by Rai. Later on, it was able to instantly shift places between TG University Hospital and the Higashikata House. In addition to its ability to teleport directly between locations at a distance, Wonder of U can also move rapidly within a smaller area by gliding along and within flat, reflective surfaces.
Though Wonder of U is an automatic stand, Tooru seems to have a limited ability to control Wonder of U directly, effectively allowing him to be in two places at once. When Tooru is actively controlling Wonder of U, his eyes glaze over and have a dull look. When Tooru is back in control of himself, Wonder of U seems to stand facing a wall if it is not actively reacting to a pursuer. If someone observes the stand in this state, they will see Satoru Akefu with his eyes dull and glazed over.
While the specific stat rankings for Wonder of U are not known, it has demonstrated proficiency in using its cane as a defensive tool. It has been shown rapidly deflecting a flurry of frozen bubbles as well as deflecting a precision shot from Josuke.
Wonder of U's main ability revolves around the concept of 'Calamity', bringing impending doom to anyone pursuing Tooru or Akefu (the Stand's 'human' form). The pursuit does not have to be in the form of a direct chase, as even the intention, will, or desire to pursue Wonder of U in the future will cause the stand to activate. The intent to pursue seems to need to be more than just coincidental, however, as Akefu had to coax a declaration of intention out of a reporter who threatened to expose him. Only when the reporter's intention was clearly stated to be in pursuit of Akefu and the Rokakaka was Wonder of U able to kill the reporter with a calamity. This is in contrast to the crowd of hundreds of people who came to the hospital with the specific intention of listening to a presentation given by Akefu, none of whom were affected by a calamity.
It is also possible to act in a way which would cause Tooru or Wonder of U to pursue the target, instead of the other way around. This makes it possible to close the distance with the user or the stand.
The exact form the calamity takes varies, but always involves redirecting aspects of the nearby environment towards the target in a harmful manner. Upon contact with any object influenced by part of the calamity, the target receives an extremely disproportionate amount of damage, especially from impacts. The damage the object can cause will only affect the target, and not obstacles in the way or bystanders unaffected by the calamity. Objects touched directly by Wonder of U can be "charged" with calamitous energy as well, allowing the stand to create additional area hazards. If the target manages to avoid or survive a calamity, another one will always follow shortly afterwards. Examples of this ability include:
- During a pursuit of the head doctor, Rai Mamezuku tripped over an umbrella stand hard enough to cause compound fractures in both legs.
- A bus containing the head doctor kicked up a cigarette butt with enough force to penetrate Josuke's hand.
- While slicing vegetables, a minor slip of the knife resulted in Mitsuba Higashikata cutting off two of her fingers and triggered a chain reaction of events that nearly led to her being lethally scalded by oil.
- When Josuke and Rai were caught in a rain storm, the raindrops hit with the force of bullets - penetrating through limbs and doing enough damage to knock Josuke unconscious and require a trip to the hospital.
- At the hospital, a police officer who Josuke knocked out fell on top of him, breaking two ribs and damaging his left lung in the process.
- A leaf on the Higashikata estate fell with enough force to slice off Joshu's fingers.
- The instant Yasuho continued to pursue Tooru at the Higashikata estate, a piece of an airplane 10,000 meters above ground broke off and fell directly towards her.
The stand can even influence the Locacaca's 'Equivalent Exchange' - when Josuke tried to drink the serum while still intending to pursue Wonder of U, the exchange happened in a way that threatened to suffocate him. Only when someone else without the intent to pursue administered the serum for him was it able to perform a normal exchange.
Wonder of U will apply calamitous effects to any object in the area of the target in an attempt to kill or disable them. When Rai was testing the limits of Wonder of U's ability while in prison, he was attacked by spilling liquid and an exploding light bulb. When those calamities failed to damage him, a normal tray of food suddenly became diseased, and erupted with maggots and a dying rat.
In the absence of any objects which can be propelled at the target to create an impact, Wonder of U seems to have the ability to affect nearby people and influence their behavior or actions. This was first seen in the Hospital parking lot when a nearby patient got unusually angry with Josuke and advanced to touch him. When Jousuke prevented contact using his bubbles, the man's neck snapped 90 degrees to the side, killing him instantly. This has also been observed with a prisoner going into a rage and attacking Rai and Joshu going berserk and attacking Yasuho.
Dying from a calamity or losing the will to "intend to pursue" either Tooru or Akefu will remove the target from the calamity priority stack.
It is revealed in Jojolion chapter 108 that even after Tooru's death, Wonder of U can act on its own and cause calamities to an individual by entering their body.