Explain Harry Potter's scar in Harry Potter and the Sorcerer's Stone.
The story of the scar goes back to when Harry Potter was a baby. Lord Voldemort had gone looking for James, Lily and Harry Potter because of a prophecy that Harry would ultimately be his downfall if not destroyed first. Voldemort killed both of Harry's parents, who died as they tried to protect the baby, and tried to kill Harry as well, but was unable to. Lily Potter had used an ancient sacrificial magic to protect the baby, so that when Voldemort tried to execute the "killing curse," it backfired. The "killing curse" left Voldemort near death, and for Harry, only a permanent scar on his forehead, in the shape of a lightning bolt, a lifelong reminder of what happened to his parents.
Harry's lightning-bolt scar is described as the only part of his physical appearance that he likes about himself in the first book. He got the scar when Voldemort tried to murder him when he was only one year old. Voldemort had already murdered his parents when he turned to Harry. The sacrifice of Harry's mother, however, activated a very powerful and deep magic that repelled Voldemort's curse and actually resulted in the demise of Voldemort rather than Harry. We later find out that when Voldemort tried to kill Harry, a part of his soul was actually transferred to Harry. Thus, Harry gained some of Voldemort's powers, including the ability to speak Parseltongue. Also, Harry has limited access to Voldemort's mind. When Harry uses this mental connection, or when Voldemort uses it, Harry feels intense pain in his scar.