This page contains trivia for "Merry Christmas Charlie Manson!". Remember, trivia must be factual, provable, and it is always best to cite your source for not-so-obvious trivia. If you would like to dispute a trivia point, please discuss it in the article comments.
All the Cartmans talk the way Eric does (e.g. "authoritah", "myah" instead of "here") implying he inherited it from his family. Elvin Cartman sounds nearly exactly like Eric only his voice is higher pitched and childish. Only the men in the family seem to have this vocal inflection.
The title "Merry Christmas Charlie Manson!" (and when the characters shout it to Charles Manson later in the episode) is referencing "A Charlie Brown Christmas" special and the phrase "Merry Christmas Charlie Brown!" from the cast.
Mrs. Cartman and Eric sing a variation of the song "Over the River and through the Woods" substituting "river" with "meadow" and "grandfather" with "grandmother". The song originally was a poem written by Vanyel Willis-Parker in 1844.
Charles Manson really has a Swastika engraved on his forehead that was modified from an X.
Manson says "Folks need to understand that I am terror! I am fear!" This is paraphrasing his interviews on television talk and news programs. He has never referred to himself as "terror" or "fear" however.
Charles Manson has a heart-to-heart talk to Stan about family where he tells them that he had a "family" once and all they were was "a gang of people I thought were my friends. Ah after we killed a bunch of people together, I realized that my real family was who took care of me and who took the time to care about what I did". This is quite the interpretation of the events surrounding the Manson murders. Manson had a group of followers that were dubbed the "Manson Family" who he had authority over and ordered to go out and kill people.
Charles Manson uses the 1960s slang term for police and normal citizens when he says "I can't wait to get out among the pigs". This also references the word painted with blood at the crime scene.
One of the books that Charles Manson has written since his "reformation" is "Are you There God? It's Me Charlie." which is a parody of the Judy Bloom novel "Are You There God? It's Me, Margaret". The story is of a young girl coming of age.