- “ Mr. McClure, what does DNA stand for ??”
Billy (voiced by Tress MacNeille) is Troy McClure's assistant who appeared in "Lisa the Simpson", "Bart the Mother" and "The Boy Who Knew Too Much". He was supposed to appear in more episodes but due to McClure's voice actor Phil Hartman's untimely death he was retired along with McClure. He is a child who appears in Troy McClure's educational films. His movies include "Birds: Our Fine Feathered Colleagues", and "In The Kitchen with DNA".
- Episode – "Bart's Inner Child"
- Episode – "The Boy Who Knew Too Much"
- Episode – "Lisa the Simpson"
- Episode – "Bart the Mother"
|Ms. Albright | June Bellamy | Belle | Billy (actor) | Booberella | Colin | Cosine | Crazy Cat Lady | Michael D'Amico | David (Treehouse of Horror XVI) | Devan Woosterfield | Dia-Betty | Mia Farrow | Ginger Flanders | Mrs. Glick | Adil Hoxha | Bernice Hibbert | Cookie Kwan | Lester | Audrey McConnell | Medicine Woman | Mrs. Muntz | Lindsey Naegle | Manjula Nahasapeemapetilon | Opal | Poor Violet | Lois Pennycandy | Pepi | Phillips | Brunella Pommelhorst | Ronaldo (Blame It on Lisa) | Dr. Simpson | Agnes Skinner | Brandine Spuckler | Jitney Spuckler | Whitney Spuckler | Spud | Dolph Starbeam | Clara Stetson | Gino Terwilliger | Dame Judith Underdunk | Veronica | Vicki Valentine | Plopper|