- "I knew you can do it. I knew you can do it. Yeah."
- —Billy Matthews
Billy Matthews is a young boy who has autism, but he is very good at basketball, and he easily beats Riley Freeman and the Timid Deer Ball-A-Holics in the climactic match. He only appears in "Ballin'".
Though he's not really an antagonist, he ironically stole Riley's dreams of basketball fame, and he even has a movie made about him starring Haley Joel Osment.