Death Echo is a type of trapped Ghost. The spirit is stuck reenacting its death over and over in a loop. Sometimes the spirit can be shocked into moving on, particularly by someone with whom the deceased has an emotional connection.
An occasional by product of murder; a Death Echo is considered one of the more pitiful spirits in the series. They are spirits who are trapped in an endless cycle of their murder and the pain of their death, usually haunting places where they lived or died. An Echo can be shocked out of the cycle and then pass through into the afterlife if they are confronted or calmed by a person they share an emotional link with. They are shown to disappear in a flash of light.
While investigating the Morton House, the Ghostfacers and the Winchesters find it filled with the Death Echoes of people who's bodies had been stolen by Freeman Daggett from the hospital morgue. After being killed by Daggett, Corbett became a Death Echo but was snapped out of it by Ed Zeddmore who he had feelings for. Corbett was then able to destroy Daggett and save his friends. ("Ghostfacers")