Uncle Hazel is the nickname Karl uses to refer to his aunt Hazel, his mam's sister. Although she now identifies as a lesbian, at one point she had been dating a man who looked remarkably like Ken Dodd but was unhappy about the fact. Though he tried not to, when Karl met him, he immediately said, "Nice to meet you, Ken". Another version of this story as told by Karl is that his father was the one who met the Dodd look-alike.
Hazel had a haunted house, with a bike in the hall and the pedals used to go backwards on their own, and shoes used to stick to the wall, "or something".