Cameo

Cameo (カメオ) is a minor antagonist featured in Part III: Stardust Crusaders.

Personality
Cameo was a cowardly man who liked to toy with people's hearts, and often acted as a "genie" who turned the wishes of his victim against them.

His strategy consisted of disguising his Stand Judgement as a wish-granting genie to his target, and then attacking them while their guard was down. He could fabricate additional beings with his stand (he often chose those who the target had an emotional attachment to) to further the illusion of being a "genie". He lacked a "fatal connection" with his Stand (meaning if the clones were destroyed he wouldn't be injured), so he elected to hide nearby and let his Stand do his dirty work. He often shouted "Hail 2U!" after granting a wish, and he later used it as a battle cry.

Stardust Crusaders
Cameo is one of the mercenaries hired by Dio Brando to kill Jotaro and his party, waiting on the island where Joseph is visiting Avdol's father. Cameo spends the entire time underwater, inside a hole dug by himself, wearing swimming goggles and a breathing straw. With the lack of damage connection between him and his stand, Cameo allows the automatic stand to do all the work while he watched closely. He uses his stand Judgement to make Polnareff believe it to be a genie and express his three wishes. Polnareff asks it to revive Sherry Polnareff and Mohammed Avdol, and so Cameo creates clones of them who end up attacking Polnareff. The real Avdol shows up and saves Polnareff from the clones, destroying them and finding Cameo's hideout. Much more easy-going than before his "death", Avdol suggests to Polnareff that they should torture him a little, blocking his breathing straw with his finger for a few seconds and laughing, all the while Cameo suffers with the lack of air. The pair end up urinating into his breathing straw, which prompts a terrified Cameo to reveal himself and beg for forgiveness. Avdol refuses and uses Magician's Red to burn him as his fourth and last wish.

JoJo's Bizarre Adventure (SNES)
The group encounters Cameo in a very different way portrayed in the manga. In Pakistan, the player finds him on the 2nd floor of a Big Mansion where, after opening a treasure chest, Judgement will appear stating that it will grant the group three wishes. The first wish it grants is to level up the group, which requires fighting three clay dolls of Jotaro. The second wish allows the group to find Hol Horse, though this turns out to be a clay doll as well. The final wish pits Judgement itself against the group with the exchange of Dio's secret as prize. Once Judgement is defeated, Cameo himself will appear and admit that he does not know anything about Dio, but urges the group to travel to Egypt to find a Stand User who is presumably not working for Dio.

JoJo's Bizarre Adventure: Heritage for the Future
Cameo appears as a computer-controlled oponent in the PlayStation port of the game, encountered in Story Mode by Polnareff in a special boss battle where the player needs to defeat Judgement, a clone of Avdol and one of Sherry. Because of the abstract and situational nature of his stand, it is likely that he would not have fit in with the concept of a fighting game as a playable character.

Trivia

 * Cameo and his Stand might be a reference to how malevolent genies were portrayed in old folk tales. They would grant a wish (or one possible interpretation of the wish) but it would often carry drastic and sometimes deadly consequences for the wisher. This of course, was to illustrate there was a dire price for interfering with fate. (Example: A man wishes for fifty thousand dollars, and later that day gets a phone call his son has been killed, and he is collecting the life insurance settlement.)
 * The English version of the Playstation port where Cameo can be fought changed how Avdol and Polnareff played around with him. Instead of urinating at his breathing pipe, they dropped pebbles on it, causing a similar but less-disturbing torture.