 Rumours fly around the school regarding the history of the Chamber of Secrets , and for Harry and his friends , the answer comes by way of Cuthbert Binns , the ghostly professor of History of Magic : The Chamber of Secrets , which houses a terrible monster , was created by one of the school ’ s founders , Salazar Slytherin , after a fundamental disenfranchisement with the others ( Godric Gryffindor , Helga Hufflepuff , and Rowena Ravenclaw ) , believing that students of non @-@ magical parentage should be refused entry to the school . When a Bludger , one of the balls involved in Quidditch , chases after Harry instead of zigzagging toward any player it can hit , breaking his arm , Dobby returns in the middle of the night to visit Harry in the hospital wing , revealing that it was he who charmed the Bludger and sealed the gateway at King ’ s Cross and that the Chamber of Secrets had been opened before . Another attack occurs , this time to a first @-@ year Gryffindor named Colin Creevey who idolizes Harry , and the school enters panic mode , setting up a dueling class for the students ( led by Lockhart and Potions master / Head of Slytherin House Severus Snape ) , during which it is revealed that Harry can speak to snakes . 
