¡°There was a big black thing,¡± said Harry, pointing uncertainly into the gap. ¡°Like a dog¡but massive¡¡±
Harry stood there, gazing at the miraculous map. He watched the tiny ink Mrs. Norris turn left and pause to sniff at something on the floor. If Filch really didn't know¡he wouldn't have to pass the Dementors at all¡.