They had just turned the corner when they heard quick footsteps behind them. ‘Percy!’ hissed Ron, pulling Harry behind a large stone griffin. Peering around it, however, they saw not Percy but Snape. He crossed the corridor and disappeared from view. ‘What’s he doing?’ Harry whispered. ‘Why isn’t he down in the dungeons with the rest of the teachers?’ ‘Search me.’ Quietly as possible, they crept along the next corridor after Snape’s fading footsteps. ‘He’s heading for the third floor,’ Harry said, but Ron held up his hand. ‘Can you smell something?’ Harry sniffed and a foul stench reached his nostrils, a mixture of old socks and the kind of public toilet no one seems to clean.