Yeah, there was one living underneath my school. And it was really huge.

(Huge for a twelve year old wizard that is. Though it may be dead in his world, its fangs and venom were still handy in destroying Horcruxes as they did managed to destroy Voldemort’s Diary and Hufflepuff’s Cup.)

The reason why it was there is because one of the founders of my school had a disagreement with his fellow founders over who they can allow to enroll to the school, so he left the school entirely bitterly but not before leaving the Basilisk in the underground chambers.