Black, who had just emerged from Azkaban, had clearly not learned to rein in his violent temper. After all, being tortured by Dementors for twelve years left anyone with anger that needed an outlet.
So when Black saw Kreacher weeping and muttering to himself on the experiment table without ever saying what item Li Feng had taken, the resentment bottled up inside him made him want to vent by beating Kreacher.
Fortunately, when Dumbledore had headed to the Black Family Home, he had put some chocolate in his pocket. Eating a piece of chocolate could counteract the Dementors' happiness-draining attack, and it was also an effective way to recover after encountering Dementors.
Handing the chocolate to Black, Dumbledore said, "Black, order Kreacher to tell us what Austin took."
Black wolfed down the chocolate. Feeling much better, he looked at Kreacher and ordered, "Now. Immediately. Tell us what item was taken."
Under Black's command, Kreacher stopped crying and said softly, "It was a Locket. It is the most evil item in this house. Before Master Regulus died, he ordered Kreacher to destroy it, but whether Kreacher drilled it with a drill or chopped it with an axe, Kreacher could not damage it. Kreacher disappointed Master Regulus."
Dumbledore asked, "What did the Locket look like?"
Kreacher looked at Dumbledore as though he had only just noticed him. He bowed respectfully and said, "Good evening, Lord Albus Dumbledore, the greatest white wizard in the Magic World. It was a Locket with an S-shaped serpent engraved on its casing. Master Regulus stole it from the Dark Lord. There is a secret of the Dark Lord inside the Locket."
Dumbledore froze for a moment, then seemed to mutter to himself while also questioning Kreacher. "A snake? A Locket connected to the Dark Lord... Is it