“Before we go any further, I think we’d better check,” whispered Hermione, and she raised her wand and said, “Homenum revelio.”
Nothing happened.
“Well, you’ve just had a big shock,” said Ron kindly. “What was that supposed to do?”
“It did what I meant it to do!” said Hermione rather crossly. “That was a spell to reveal human presence, and there’s nobody here except us!”
“And old Dusty,” said Ron, glancing at the patch of carpet from which the corpse-figure had risen.”