One of the popular fan theories surrounding the Harry Potter series is that of Harry and his encounters with the Dementors. The theory is based upon the frightening scream that Harry hears before he blacks out from the Dementors attacks. The nightmarish hooded figures are known to suck out a persons emotion, effectively draining them of their happiness. Dementors force you to relive your most painful memories, which leads to them eventually sucking out your life force.
It is widely known Harry Potter theories that he is affected worse than others by the Dementors due to the trauma that he has suffered. When he is attacked by the Dementors, he is forced to relive the death of his mother, Lily, and the sound of her screaming his name before she is killed. The premise of the theory is that it is not Harry’s memory that he is reliving, but Voldemort’s instead. Since Harry was only fifteen months old when Lily was killed makes it plausible that the memory he relives is that of Voldemort’s due to the fact that part of his soul resides in Harry. It is believed that the memory is a product of Lily sacrificing herself for Harry, causing Voldemort to experience unrelenting pain, bringing him the closest to death he had been. Contemplating the fact that his mothers voice is the last thing he hears before he blacks out, it’s reasonable that it could be Voldemort’s memory since it was right before he was torn from his body.