The real serial killer who is often associated with a hockey mask is Jason Voorhees, but it's important to clarify that Jason is actually a fictional character from the "Friday the 13th" horror movie franchise. He is depicted wearing a hockey mask and is known for his violent behavior.
In reality, many serial killers do not have a specific iconic look or costume like Jason. However, no real-life serial killer is specifically known for wearing a hockey mask in the same way. Most serial killers operate in secrecy and do not have public personas that involve costumes or disguises. If you have more specific aspects of a case or character in mind, feel free to share!