Rubber Soul

Rubber Soul appears in Part III: Stardust Crusaders as the central antagonist of the arc Yellow Temperance.

Impersonating Kakyoin, Rubber Soul isolates and attacks Jotaro and the Runaway Girl in Singapore.

Appearance
Rubber Soul is a medium-height curly haired man, with his Stand granting him the ability to grow larger and to change appearance at will.

Personality
Rubber Soul was hired by Dio with the promise of earning 100 million as a reward for killing Jotaro.

He has a rather disturbing personality: he is extremely rude and impolite, showing no respect nor mercy for people and animals, as they are beings that he only sees as food for his Yellow Temperance. He does not seem to be particularly intelligent, though he has a really bad temper: he wanted to ambush Jotaro with Kakyoin's appearance, but his unusual behavior blew his cover.

Rubber Soul is also very violent: he attempts to kill a pickpocket by breaking his back, and remorselessly eats a dog under the eyes of its master with his Stand. In order to grow bigger, he did not hesitate to eat bugs either.

In spite of this, he is very cowardly, giving away the names of his allies in order to escape Jotaro's wrath.

Abilities
Rubber Soul's Stand is Yellow Temperance; a sticking, rubbery mass bound to and encasing his body; defending him from all brute attacks, andwith which he may effectively impersonate others.

Yellow Temperance
While Jotaro Kujo and his companions were in Singapore, looking for tickets to travel to India, Joseph Joestar and Mohammed Abdul decided to anticipate Dio Brando's next move, by means of Joseph using Hermit Purple on a television, trying to get a video of the vampire. Before being able to locate Dio, the Stand warned his master about the coming danger: by joining voice segments from different TV programs, Hermit Purple informed about Noriaki Kakyoin being a servant of Dio.

However, Joseph's stand actually presaged Rubber Soul's presence and modus operandi, since he secretly used his Stand to take Kakyoin's appearance and ambush Jotaro while he is alone with the Runaway Girl. Jotaro begins to be suspicious about "Kakyoin"'s strange behavior: when Rubber Soul tries to push him from a balcony, Jotaro believes Kakyoin to be possessed and punches his face.

After hitting him, Rubber Soul's real power is revealed. Being unable to destroy Yellow Temperance by burning and freezing it, Jotaro drags Rubber Soul underwater, taking advantage of the wielder's human frailties to defeat his stand. Jotaro punches a now defenceless opponent, forces him to reveal the power of J. Gail's Stand.

Rubber Soul tried to finish Jotaro with a last surprise attack, but Jotaro managed to counter it by exploiting water pressure. The now defeated Rubber Soul tries to save himself by saying that he was just kidding, but Jotaro replied by saying "Kidding? Then, let's laugh together" and proceeding to attack him with countless punches by Star Platinum. It is unknown if Rubber Soul was actually killed in the process.

JoJo RPG (SFC)
In the game, Rubber Soul instead briefly imitates Devo and battles the player's group on a hotel rooftop.

Heritage for the Future (PS1/DC/Arcade)
Rubber Soul is one of several characters added in the arcade update. Looks-wise, he is a palette swap of Kakyoin with a taller build and a different face, and his stand is a yellow coloured Hierophant. He is not encountered in the Story Mode by any of the main characters (arcade version), but retains his own storyline as a secret character.

In his own story, Rubber Soul is hired by Dio to assassinate Jotaro and his companions. His story lacks any notable cutscenes, aside from the ending after the player defeats all of the heroes. He claims that he is the luckiest man in the world, and that no one else could earn one-hundred million dollars by fighting for only a few minutes.

He is also encountered as a normal enemy in the PSX port's Super Story Mode. The Player will receive a Secret Factor bonus if they allow him to perform his "Rero rero rero" taunt.

Strategy
Rubber Soul might essentially be a palette swap of Kakyoin, but his playstyle differs greatly. He lacks an active stand, and instead elects to call Yellow Temperance to the battlefield temporarily for his special attacks. His moves tend to be slow and clumsy, as he cannot block or perform any follow-up attacks (aside from his light punch) while Yellow Temperance is still visible on the screen.

His special attacks involve Yellow Temperance (in the form of a yellow colored Heirophant) shooting yellow acid balls at the opponent in short range. Within that same range, he can grab the opponent and break their back over his shoulders. He can also throw Yellow Temperance along the ground to ensnare the opponent's legs.

His special stand technique allows Rubber Soul to counter an oncoming attack by forming a rubbery shield around his torso and knocking the opponent airborne. This is commonly followed up by his first super technique.

Rubber Soul's intro mimics a scene from his initial appearance, during which he eats several beetles and grows in size, making the sprite different from Kakyoin's. Also, if Alessi uses his Stand power on him, Rubber Soul does not turn into a child, but rather reverts to the fat woman he took the appearance of on the cable car.

Stardust Shooters (Android/iOS)
Rubber Soul appears as one of the several PART III characters who posses a Metal Striker. His FINISH MOVE makes the enemy get involved by Yellow Temperance, wich melts and causes damage.

Trivia

 * During the battle with Jotaro, Rubber Soul references Mike Tyson, saying that not even the famous boxer would be able to earn 100 millions (his prize promised by Dio for killing Jotaro and the others) by fighting for a few minutes.
 * Rubber Soul is the first character seen using the "rero rero rero" tongue-rolling sound. This may be a pun on his stand, Yellow Temperance, as "rero" sounds similar to "yero" (yellow in Romaji).