Isaacs took great joy in making Lucius Malfoy as cruel and unlovable as humanly possible. During a scene in The Chamber of Secrets, he decided to improvise a physical gesture at the end of a take by violently swinging his leg and cane outward. The sudden, aggressive movement caught director Chris Columbus completely off guard, prompting him to call a swift halt to the shoot. Believing the actor had experienced a mishap on set, Columbus called out to the crew to quickly clean up the floor because Isaacs had slipped. Isaacs immediately corrected the director in front of the entire crew, proudly clarifying that he had not slipped at all, but was instead pretending to kick Dobby the house-elf straight down the stairs.
