why does the basilisk lizard run on water
Common basilisk When startled, the common basilisk escapes by speeding to the nearest edge of water—and continues sprinting. The lizard runs on only its hind legs in an erect position, holding its fore legs to its sides. This basilisk is so adroit on water because its feet are large and equipped with flaps of skin along the toes that allow it to catch on tiny air bubbles. When moving quickly, the lizard can cross a surface of water before sinking. On water, it runs an average speed of 8.4 km/h (or 5.2 mph), which is just a little slower than its speed on land. Younger basilisks can run 10 to 20 meters on water, while adults cross only a few meters before sinking. Adults do not move slowly, but they weigh more and cannot sprint for as long a time. Once a basilisk submerges, it continues swimming until it is sufficiently far from its pursuer—if the predator has followed past the bank. Although this lizard stays close to water to escape terrestrial predators, it swims only when necessary because some other aquatic animals would eat the basilisk given the chance.
Rubeus Hagrid Readers first discover why Hagrid was expelled from Hogwarts in the second novel. It is revealed that Hagrid was a student at Hogwarts at the same time as Tom Marvolo Riddle, the wizard who later became Lord Voldemort. Hagrid was expelled during his third year, after being caught in the company of Aragog, a dangerous acromantula: this already serious crime seemed worse than it was, due to the belief that the acromantula was "The Monster of Slytherin", and that Hagrid had released it from the Chamber of Secrets and allowed it to attack students. Aragog escapes into the dark forest and starts a colony of spiders. The belief of Hagrid's guilt was encouraged by Tom Riddle, the actual criminal, who had been using the true monster (a basilisk) to attack students, and who had framed Hagrid to prevent the school from being closed, because he didn't want to return to the orphanage whence he had come. During the events of the second book, the Basilisk is unleashed once again and Hagrid is sent to the prison of Azkaban, as he is believed again to be responsible for the attacks. However, before being arrested, Hagrid tells Harry and Ron to "follow the spiders", so that they can meet Aragog and discover the identity of the true monster. After Harry defeats the Basilisk and uncovers the truth, Hagrid is freed from prison.