Having five kids comes in handy for Grindhouse director Robert Rodriguez. He jokes to Jay Leno on The Tonight Show that he finds his four sons, Rocket Valentin, Racer, Rebel Antonio, Rogue and daughter Rhiannon Elizabeth, 1, with his estranged wife Elizabeth Avellan, useful on his films when he’s in need of a few extras.

Only one of them, though, can be seen in Grindhouse.

Someone who does know Rebel’s alter ego’s fate is Robert’s mom, who dozed off during a screening but woke up just in time.

Asked about his children’s unusual names, Robert attributes them to side effects he sustained from his college years when he subjected himself to medical tests to make extra money.