Opal NecklaceThis necklace was on sale at Borgin and Burkes in Harry's second year when he accidently flooed himself to Knockturn Alley by saying "Diagonally" instead of "Diagon Alley". Draco had been looking at it, but was sent away by his father. Then, in Harry's sixth year, someone sent this cursed necklace to the castle from the Three Broomsticks. Katie Bell was under the Imperius Curse and was told to bring this up to the castle. She accidently touched it, however, and was sent flying into the air. Luckily she only touched it withthe tiniest bit of skin possible, or she could have died. Later we find that Draco had been the one to send this by using Madam Rosmerta (under the Imperius Curse as well) to stand on the other side of the Girl's bathroom and curse the first Hogwarts student to come in. This happened to be Katie Bell. Draco had been trying (half-heartidly, I might add) to get this necklace, and the poisoned oak matured mead, to Dumbledore. Both ways, the selected attempts were taken by someone else. First by Katie Bell, then Ron Weasley.