Madam Octa is Larten Crepsley's venomous spider. Madam Octa has a unique and beautiful color as a spider, and can do many different tricks. She is highly intelligent and venomous, she can even be trained to control how much poison she injects. She can live up to 30 years, according to the monk who sold it to Mr. Crepsley. Supposedly, her bite is untreatable, however it is revealed Mr. Crepsley posesses an antidote. This is discovered when Darren stole her and following this she bit Steve; forcing him to go to Mr. Crepsley asks for a way to save him, revealing the antidote exists. In order to save him, Darren is forced to become a half-vampire and his apprentice. Later in the series, Darren releases Madam Octa into the cave of spiders inside Vampire Mountain, where she mates and produces offspring, which are named after Darren; Ba'Shan's Spiders. Madam Octa and Larten Crepsley appear on the glossy new cover of Cirque du Freak. Her history is more explained in Saga of Larten Crepsley. The spider’s color schemes look similar to Spider Man.