It is an invulnerable Automatic Sentient Stand that, once ordered by the user, uses saliva to dissolve parts of its target. However, if more than one person is observing it, the Stand acts like a loyal servant and follows every command.
Yo-Yo Ma appears as a short, rotund dwarf with a pickelhaube spike protruding from its head, reminiscent of the one worn by its user. It possesses a scaled body and wears overalls holed to show the knees. Its design is based on the various forest fairies in Grimms' Fairy Tales.
Yo-Yo Ma is indestructible, and will even relish its pain in a masochistic fashion. It seems to have a fixation with eating things and can often be seen drooling excessively. When it is assigned a target by its user, Yo-Yo Ma will follow them and obsequiously assist them in any way possible. This is to make the target drop their guard. Yo-Yo Ma also has a speaking habit of referring to its targets as "master" and saying its own name randomly.
Yo-Yo Ma is an Automatic Stand characterized by its high range, autonomy, and resilience, allowing D an G to sic it on Jolyne Cujoh and wait from afar until Yo-Yo Ma kills her with its saliva. Yo-Yo Ma is shown capable of consuming and holding objects without harming them. Yo-Yo Ma also secretes a repulsive stench when an object is attempted to be retrieved from its stomach, such as when Diver Down was used in an attempt to remove The Green Baby from Yo-Yo Ma's stomach. In addition, Yo-Yo Ma can store and carry a variety of miscellaneous objects in its pockets. Yo-Yo Ma is shown to be near indestructible, taking six shots from a pistol, getting punched multiple times by Stone Free without taking any damage, and wasn't even killed when disabled by Narciso Anasui with the user instead being beaten.
As an automatic Stand, Yo-Yo Ma is given broad instructions by its user and will fulfill them the best it can. The particular trigger for its attack is when its victims are distracted and stop watching it but as long as more than one person looks at it, then it'll keep acting subservient and obey any command. The spike on its head is actually the sensor that allows it to automatically detect when its targets are distracted and it can be sabotaged with the right power. Thus, Anasui connected Yo-Yo Ma's sensor with the brain of a frog via Diver Down so that Yo-Yo Ma would be constantly distracted by the instincts of the frog.
Unlike most automatic Stands, Yo-Yo Ma possesses a high degree of intellect. It knows a fair deal about survival in the swamps, knows how to pilot a hovercraft, and can craft miscellaneous useless items out of junk, like a chair out of twigs. The only instructions it receives are general goals to achieve such as killing its target and retrieving the Green Baby. It is then free to act as it pleases and will dispose of any person in its way.
Strangely enough, Yo-Yo Ma as a Stand has demonstrated the ability to urinate.
On the surface, Yo-Yo Ma appears as a harmless and surprisingly helpful Stand. However, when it is not being watched by more than one person, Yo-Yo Ma can produce an acidic saliva or drool, which it uses to dissolve parts of its targets body.
It is able to dissolve whole chunks of flesh without causing pain or blood loss. The dissolution of flesh is completely silent and abrupt, capable of destroying Foo Fighters's jaw in an instant. It has multiple ways of dispersing its saliva, such as inserting it into the bodies of biting mosquitoes and mixing it with water in front of a moving boat to cause it to splash those on-board. It can even position vinyl strips so that they rub against the propellers of an airboat and generate static electricity, which will make its spit waft in the air. Humans are seemingly the only beings that are affected by its saliva, allowing it to use mosquitoes to spread it.
After Jolyne Cujoh, Narciso Anasui and F.F. escape from the maximum punishment ward, Yo-Yo Ma appears suddenly and swallows the sphere containing the still-forming Green Baby. The three escapees use their Stands to pummel Yo-Yo Ma into the ground but are unable to retrieve it. Even Diver Down proves ineffective, as Anasui can "feel" the enemy Stand's stench through his own. Yo-Yo Ma suddenly starts acting overly-friendly - creating a chair out of branches for Jolyne to sit on, offering her a comic book, cleaning her shoes and catching a bee that flew too close. Unable to do anything about the enemy Stand, Anasui and Jolyne take it with them as they flee by motorboat and leave F.F. to find and kill its user. Before parting with her, however, Yo-Yo Ma makes sure to melt part of her face with its acidic saliva while the other two aren't looking.
When the pursuing prison guards almost discover Anasui and Jolyne's motorboat hiding in the marsh, Yo-Yo Ma helps them to camouflage themselves and the boat to look like water rushes. Unfortunately, they are found anyway and, while Jolyne's attention is focused on the guards, Yo-Yo Ma releases a mouthful of mosquitoes containing its acidic spit. Shortly after, Anasui punches him off the boat and into the guards as a distraction. After commandeering the guards' motorboat and resuming their escape, Jolyne comes to realize that she is unable to speak due to the large holes in her tongue and correctly assumes they are the result of the enemy Stand's attack. After Yo-Yo Ma attacks her a second time, incapacitating her, Anasui finally realizes that the enemy Stand is not friendly at all. However, his attempts to discern Yo-Yo Ma's method of attack only result in him receiving the same sort of injuries as Jolyne. Ultimately, he ends up implanting a frog in Yo-Yo Ma's head and connecting its brain to the target sensor - thus causing the Stand to act and think like a frog. Yo-Yo Ma then becomes unable to fulfill its intended function or even to keep its concentration for any longer than a few seconds. Only when F.F. kills D an G does Yo-Yo Ma implode and blow away as dust.
Chapters / Episodes
- “Stop treating me like an object... not that I mind.”
- “Yo-Yo Ma... do you still not understand? It doesn't matter if you destroy parts of my body, there is no way you can destroy me or stop me. You cannot destroy my target radar, or prevent me from attacking Jolyne Cujoh... The only way you two could have survived is if you had run away.”
- The essence of horror where you are unable to look away from something is the main idea behind the Stand.
- Yo-Yo Ma's voice actor in the anime, Kappei Yamaguchi, previously voiced Forever in Stardust Crusaders and Shigechi in Diamond is Unbreakable.