Divination
On Harry’s first day at Divination, he saw the Grimm in his teacup, and Trelawny  freaked out, saying how it was the omen of death. At the end of Prisoner of Azkaban, we all thought it was Sirius, because his animagus form is a big black dog, but Trelawny was actually right when she predicted Harry’s death,because Harry did die, but came back after.
In Prisoner of Azkaban, at Christmas, there’s twelve people around the dining table, and Trelawny comes along. Albus invites her to eat with them, but she freaks and tells him that when thirteen dine together, the first to rise will be the first to die. But, Ron had Scabbers in his pocket, which meant there were already 13 people. And Dumbledore got up first.Â
DIVINATION IS REAL PEOPLE