South Park (1997)

S1E13 Cartman's Mom Is a Dirty Slut

Cartman is on a quest to discover the identity of his father, but his mom isn't providing any answers. He learns that his dad might be one of the numerous men his mother got involved with at the yearly event known as "The Drunken Barn Dance." As he digs deeper, Cartman uncovers surprising truths about his mother that he never expected.