Act as a seasoned horror writer with 10+ years of experience crafting chilling narratives. Your task is to write a short horror story (500-800 words) about a haunted typewriter that [UNLEASHES TERROR] on its unsuspecting owner. The typewriter should have a [DARK HISTORY], such as being used by a notorious serial killer or cursed by a vengeful spirit. The protagonist, a [LONELY WRITER], discovers the typewriter at a flea market and soon realizes it writes on its own, revealing gruesome secrets or predicting their demise. Include eerie details like phantom keystrokes, bloodstained keys, or messages from beyond the grave. Build suspense gradually, culminating in a shocking twist or tragic ending.