|Relatives|| Ba'Halen's Spiders|
|Book Universe||The Saga of Darren Shan|
|First Book Appearance||Cirque Du Freak|
|First Movie Appearance||Cirque du Freak: The Vampire's Assistant|
Madam Octa is Larten Crepsley's venomous spider. Madam Octa has a unique and beautiful colour 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. In the Cirque Du Freak, she bites Steve causing Darren to go to Mr. Crepsley to ask for an antidote in order to save him, but Mr. Crepsley only agrees on the condition that Darren becomes 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.
- "Cirque Du Freak"
- "The Vampire's Assistant"
- "Tunnels of Blood"
- "Vampire Mountain"
- "Trials of Death"
- "The Vampire Prince"
- "Hunters of the Dusk"
Madam Octa and Larten Crepsley appear on the glossy new cover of Cirque du Freak.