Boris Tollar, is Caillou's father and also his secondary caregiver. His parents are Caillou's grandparents, Grandma and Grandpa. He would often ground his son Caillou whenever he did something bad. He has been appearing in almost every episode since “School Daze: The Movie”.
Boris is an angry and abusive person. He would always ground Caillou for doing bad things. Sometimes, he would take it too far with the punishments. Like for example, he cut off Caillou’s penis for peeing on the teacher. However, after the events of the Christmas Chronicles series, he started treating his son with love and care again, just like he did in the original show.
Boris has tan skin, brown eyes, and brown hair. He wears a green hoodie with red strings, blue jeans, and red sneakers. In Caillou, he wore a lime green sweater with a red border. Now he wears it underneath the hoodie.