The B-story involving all the bullies gathering to hear Chester, Bart and the gang's chase on the subway, and the various bully gangs is a parody of the film "The Warriors". The electronic music is in the style of Tangerine Dream which played in "The Warriors" trailer.
One of the bully groups is called Krusty's Kids, which dress in clown costumes.
This is a reference to Jerry's Kids, a charity for sick and disabled children run by comedian Jerry Lewis. In the episode "E. Pluribus Wiggum" in a conversation between Jon Stewart and Krusty, John mentioned that Krusty's Kids missed Krusty. Krusty said that they're great, though a little clingy.
Homer says his grandfather is alive, which means Mona's father would be the one alive since Abraham's dad was seen in heaven.