William "Billy" Sparks was a neighbor of Sheldon, who claimed on The Big Bang Theory that he was one of his childhood bullies. He was mentioned being on Sheldon's all-time enemies list in "The Creepy Candy Coating Corollary" and “The Shiny Trinket Maneuver", where Sheldon claimed he shoved a Mexican Peso up Sheldon's nose. He appears in the series spinoff "Young Sheldon