Bill Allen

Bill Allen and Fosse McDonald are students at South Park Elementary. They are similar to Beavis and Butt-head, calling things gay then laughing in deep voices.

Appearance
Bill wears a blue shirt similar to Butters except with a white collar. His hair is similar to Terrance's, although it is brown and slightly shorter. Fosse wears a purple shirt similar to Terrance's, except with many more stripes. His hair is black but stringy, meaning it could be a different color if it was full. They both have thick eyebrows during the first four seasons, but afterward they have regular ones.

Personalities
Bill and Fosse are bullies, often laughing at things and people. In addition, they think everything is gay; on one occasion Fosse even said "we're gay", which shows his apparent opinions on everything. Due to their seeming stupidity, it appears they did not make it to the fourth grade - they are never seen in the fourth grade classroom, but are in the halls, and are only seen in the hallway and playground after the second season. Their voices appear to sound almost the same. These two were seen again in "Lil' Crime Stoppers" when the boys discovered they stole Sarah Peterson's doll. They then played along and were "shot" in the game; however, they were just playing a game and didn't die. Bill and Fosse seem to be some of the more naive children in the school along with Butters, Jason and DogPoo. In the episode "It's a Jersey Thing", they were both part of Cartman's group to help capture and lock up Kyle. It seems that unlike most other kids, (Craig, Clyde, Token), who are more aware of Cartman's manipulating methods, these guys still haven't wised up to it and so that is why Cartman would most likely seek them out for help.

Family
Due to Bill and Fosse's quick phasing out from the series, their families were never officially seen. In the episode "Damien", two older men are seen in the bar after Jesus storms out, saying "This show's gay" followed by "Yeah, Gay" in the similar style to Bill and Fosse, while also having the same face and clothes but adult bodies. In the commentary of the episode it was revealed that these two characters were indeed Bill and Fosse's parents. Bill's dad actually has a line in "Ike's Wee Wee" where he is one of the parents that drives by and makes fun of Mr. Mackey. Bill can be seen in the episode "Best Friends Forever" with an adult woman who could be his mother.

Trivia

 * Bill is seen playing on the school's basketball team in "Elementary School Musical", one of the few times he appears without Fosse.
 * Bill and Fosse are a part of Cartman's entourage to eliminate Kyle in "It's a Jersey Thing". Although neither speak, it's arguably their first major appearance since "Lil' Crime Stoppers".
 * They are referred to by Matt and Trey within the scripts and commentaries as 'the Nerds', 'the Bullies' and the 'That's Gay Kids' - they actually rarely use the duo's real names.
 * Outside of "An Elephant Makes Love to a Pig" the two are never seen in the classroom seats at the same time - Bill is often there into the third season, and Fosse would occasionally reappear. Bill once appeared in 4th Grade Classroom B, but Fosse did not appear with him.
 * Fosse's original voice had a different pitch in the first season. In the second, third and seventh seasons, his voice is much deeper and sounds almost identical to Bill's. He also has a deep voice akin to Bill's in "An Elephant Makes Love to a Pig", though in his preceding and immediate next appearances it is at its original pitch.
 * In "T.M.I.", their names are revealed on the chart as Bill Allen and Fosse McDonald.
 * Fosse's hair looks similar to the Charlie Brown Character Pig Pen's hair.

Prominence

 * "Big Gay Al's Big Gay Boat Ride"
 * "An Elephant Makes Love to a Pig"
 * "Pinkeye"
 * "Damien"
 * South Park: Bigger, Longer & Uncut (Cameo)
 * "Professor Chaos" (Cameo)
 * "Red Hot Catholic Love" (Cameo)
 * "Lil Crime Stoppers"
 * "Butt Out"
 * "Raisins" (Cameo)
 * "Douche and Turd" (Cameo, Fosse only)
 * "Best Friends Forever"
 * "Ginger Kids" (Bill only)
 * "Tonsil Trouble" (Cameo)
 * "The List" (Cameo)
 * "Breast Cancer Show Ever" (Cameo)
 * "Elementary School Musical" (Cameo)
 * "It's a Jersey Thing"
 * "Funnybot" (Cameo)
 * "T.M.I." (Cameo, Fosse only)
 * "Cash For Gold" - Bill Allen was seen in the background on the playground.
 * "Faith Hilling" - Fosse was seen in the memeing class with the other 4th Grade students.
 * "Jewpacabra" - Fosse is seen at the Easter egg hunt.
 * "Butterballs" - Bill is seen in the background in the cafeteria. Both are seen in Stan's anti-bullying video.
 * "Cartman Finds Love" - Fosse is seen in the background on the playground.
 * "Going Native" - Fosse is seen eating in the cafeteria.