Dr. Alphonse Mephesto is an eccentric geneticist and stereotypical mad scientist, as he lives and works at South Park Genetic Engineering Ranch. Whenever the people of South Park need something beyond the natural, they turn to him. He is the leader of the North American Marlon Brando Look-Alikes, the "other" NAMBLA. He tends to put more than one ass on different animals.
Dr. Mephesto has genetically engineered many different species, such as a four (later five) - assed monkey, a four-assed ostrich, a four-assed mongoose, a mouse/duck, a gorilla/mosquito, a rabbit/fish (this is fake because Cartman said the ears are tied on them), a four-assed frog, a seven-assed Galapagos Turtle, loads of pissed off turkeys and a mutant clone of Stan.
The character is an extended reference to Marlon Brando's portrayal of Dr. Moreau in the 1996 film version of The Island of Dr. Moreau. He is even a member of the North American Marlon Brando Lookalike Association (the other NAMBLA). Like Dr. Moreau, Dr. Mephesto creates strange creatures with his talents; however, his creations are things like animals with multiple sets of buttocks. Mephesto believes it is for the good of the Earth, and that animals with one set of buttocks are inferior and must be destroyed. He even goes as far as presenting a "seven-assed Galapagos Turtle" in an attempt to win a Nobel Prize, but loses to Randy Marsh's "Unified Theory of Fart Thing". He also performs experiments ranging from simple DNA tests to creating a genetic clone of Stan Marsh for his son's project and later a clone of the Muslim prophet Muhammad.
He wears brown trousers and a yellow flowered Hawaiian shirt with an open collar, revealing chest hair. His face is wrinkled and he wears a brown hat over a bandana that covers his hair. He is usually seen walking with a cane, whose handle is shaped like a pair of buttocks. Mephesto's appearance was tweaked and cleaned up slightly in "201", including an updated collar, hat, and gray hair.
- To see images of Dr. Alphonse Mephesto, visit Dr. Alphonse Mephesto/Gallery.
Dr. Mephesto has two children, Terrance, who is in the fourth grade class with the main characters, and Kevin. Although Mephesto is shown to be Terrance's father, they are never seen together save for one episode and he is never shown with the other parents.
- Main article: Kevin Mephesto
Kevin is Dr. Mephesto's
assistant and adoptive "son". He wears similar clothing to Mephesto. He is usually described by others as "That little monkey guy". He seems on first glance to be mute, but he is rumored to have a very sweet, golden voice. He mostly follows Mephesto around. His name is revealed in "Cartman's Mom is a Dirty Slut".
Kevin's story is told in the song "Mephesto and Kevin" by Primus from Chef Aid: The South Park Album; he was apparently a failed attempt to create a perfect pop singer, a test tube baby created from Michael Jackson's sperm and the egg of an unspecified, musically talented female donor, brought to term inside the womb of a llama. It is also revealed Kevin is legally Dr. Mephesto's son.
He is seen in a crowd in "Freak Strike". Kevin is never heard speaking until the episode "201", in which he yelps in surprise when Cartman/Mitch Conner tricks their way into Mephesto's lab. He can also be heard singing at the end of "Mephesto and Kevin".
His brother has never been seen, but it was first said in the episode "Cartman's Mom is Still a Dirty Slut" that he attempts to shoot Mephesto every month on routine. Later in "201" it is revealed the real reason that he shot Mephesto is that he was a Broncos fan, and revealing that Cartman's biological father played for the Broncos may distract the team, which was having a good year.
- Dr. Mephesto is likely a Buddhist as in "An Elephant Makes Love to a Pig" he says "Oh, thank Buddha I found you boys!"
- "Cartman Joins NAMBLA" was Dr. Mephesto's last speaking role until Season Fourteen, in the episode, "201".
- Trey Parker later commented that by this point he and Matt Stone simply didn't find the character funny any more, and that they should have made him a member of the real NAMBLA to write him out permanently.
- He is the first character to be taken out of the show without dying, the second being Officer Barbrady, although Officer Barbrady did come back with a much more prominent role in Season 19.
- Dr. Mephesto seems to be based on Marlon Brando's character in the infamous bomb "The Island of Dr. Moreau", as he belongs to a Marlon Brando-look alike club, conducts genetic experiments, and has a small but deformed assistant.
- In "201", it is revealed that Dr. Mephesto surgically alters his test subjects rather than genetically.
- Comedy Central has consistently spelt his name as 'Mephisto' in press materials, however, Trey Parker's scripts including those for "An Elephant Makes Love to a Pig", "Cartman Joins NAMBLA", and "201" all spell the name as Mephesto, and the name is pronounced as such.
- His name is a reference to Mephistopheles.
- In South Park: The Fractured But Whole Mephesto says "You ever played that video game, Half-Life?" when showing the children around the complex. This likely implies that he's a fan of the Valve Franchise. (Although this was before parodying the game). Cartman also said something similar in "Skank Hunt" but about Counter-Strike instead.
- "An Elephant Makes Love to a Pig" - Mephesto's first appearance. He rejects Kyle Broflovski's idea of splicing the DNA of a pig and an elephant. Later, he helps his son to make a clone of Stan.
- "Starvin' Marvin" - Mephesto creates genetically modified turkeys, but they go crazy and put the whole town in danger.
- "Cartman's Mom is a Dirty Slut" - Mephesto offers to help Cartman find out who his father is, but only for a price.
- "Cartman's Mom is Still a Dirty Slut" - Mephesto gets shot by his brother right before he can reveal the identity of Cartman's father.
- "Prehistoric Ice Man " - Helps unfreeze and talk to the prehistoric ice man.
- South Park: Bigger, Longer & Uncut - Seen in the crowd singing Mountain Town (Reprise) at the end of the movie.
- "Spontaneous Combustion" - Mephesto tries to win the Nobel Prize with a "seven-assed Galapagos Turtle", but loses to Randy. Later, he reveals that Randy's theory about Spontaneous Combustion is causing a change in the environment.
- "Jakovasaurs" - Mephesto helps the Jakovosaur to reproduce.
- "Hooked on Monkey Fonics" - Seen during the spelling bee.
- "Are You There God? It's Me, Jesus" - Gives hormone pills to Stan.
- "Cartman Joins NAMBLA" - Suggests Cartman joins NAMBLA but Cartman joins the 'North American Man Boy Love Association.' instead of the 'North American Marlon Brando Look-Alikes' which is what he really means. Also is the spokesperson of 'the other NAMBLA' and helps the police catch the pedophile NAMBLA.
- "Freak Strike" - Kevin cameos during the freaks song.
- "Red Sleigh Down" - Cameo in the crowd.
- "I'm a Little Bit Country" - Cameo during the final song.
- "It's Christmas in Canada" - Cameo in crowd at 04:58.
- "Goobacks" - Kevin has a cameo during the final song.
- "Britney's New Look" - Seen from the side leaving and entering the crowds to take photos of Britney Spears.
- "Eat, Pray, Queef" - He appears as one of the men singing "Queef Free".
- "201"- Cartman and Mitch Conner ask him who Cartman's real dad is, and Stan, Kyle, and Kenny ask him to clone Muhammad.
- "The City Part of Town" - Cameo during the final scene in the newly opened South Park Whole Foods Market.
- "Bike Parade" - Seen watching the bike parade.
- "South ParQ Vaccination Special" - Seen waiting in line outside Walgreens for a vaccine and is later seen at the end celebrating that he has been vaccinated against COVID-19.