"It's a fake," Harry announced triumphantly. "But not like the locket Regulus Black left in that cave with the Inferi. This is an actual Horcrux, made by Riddle to fool any potential hunters trying to find and destroy them. He's created decoys, hoaxes, but he's carried out the ritual of Horcrux creation himself ... only he's used other people's souls to fill the objects, and somehow made them look like they are his. Like I said ... this is very clever, Tom!"