Phineas and Ferb episode "The Monster of Phineas-n-Ferbenstein"
Ferbgor, Ferb's Victorian ancestor, assisted Dr. Phineastein in creating a Platypus Monster and most probably any other things that Dr. Phineastein made. He is shown wearing a brown monk hoodie. He only appeared in "The Monster of Phineas-n-Ferbenstein", with Dr. Phineastein and Constance, who was probably their guardian. Just like his descendant, Ferbgor is a man of few words (Even though he is never shown talking in the episode.).