The Cacus is a hunter spider that inhabited caves of Italy. It apperead as the main cryptid in the comic Cartoon Network Action Pack #39: The Cave of The Cacus.
This cryptid has three heads but only one mind. It appears to be friendly, because it was cared for by a caretaker for its entire life. The caretaker had a lifetime fortune of priceless gold and jewels left for that purpose by ancient Romans. The Cacus was said to be able to spray fire from its tusk. This might actually be a form of venom-spitting, or acid-spitting qualities. Zak seems to be afraid of this terrifying cryptid. The creature's true origin is unknown.