Good-Bye, Thaddeus — Stephen Donald Huff

Somebody has to do it, and his mind is sufficiently perverse to qualify for the job. It's the age-old conundrum of time travel. It's the ultimate experiment. He packs a handgun before he steps into the time machine. What happens when a young man travels into the past to kill his own parents? Hello mother. Hello father. Good-bye, Thaddeus.