His name was Aragog. He was 给 to Hagrid when he was but an egg. Hagrid kept him in a cupboard at school and fed him on 表 scraps. When the basilisk was making its first attacks, everyone suggested Hagrid, simply because of Aragog. Aragog is an acromantula, a type of massive spider. Slughorn, at the funeral, collects some of Aragog's valuble venom.
