Clay James Thompson was a resident of Sioux Falls who was resurrected as a zombie alongside many other dead residents.
In 2004, Clay James Thompson, memorialized on his gravestone as "Father, Coach, Friend," died at age 37 after being shot in the back by Benny Sutton in a supposed "hunting accident". As the Apocalypse loomed in 2010, Clay was among the departed townspeople brought back to life by the Horseman Death. On the stormy night that Clay was resurrected, Benny was enjoying a wildlife documentary when he was startled by the front door of his trailer being blown open by the storm. After he went to secure it, he was horrified to see Clay, who proceeded to strangle him to death.Sam and Dean arrived to investigate the case and interviewed Digger Wells who knew all about the so-called hunting accident. He claimed to have witnessed mud-covered Clay Thompson climb into the window of Benny's trailer right before he turned up dead. After the boys verified that Clay Thompson's coffin was in fact empty, they broke into the Thompson residence to look for clues. They encountered Clay, who swung on them believing they were burglars. Once they identified themselves as FBI agents, they were shocked to find he behaved like a reasonable and regular guy. He realized they were there about Benny and readily confessed to killing him, but only because he wasn't going to let him get away with shooting him in the back. He volunteered to go with them to jail, asking only that they be quiet so as not to wake his children.
As they followed him out of the house, Dean quietly drew his gun, still intending to carry out a head-shot because he was a zombie. Sam stopped him, uneasy with cutting down a "soccer dad." Before they could further discuss what they would do with him, they were stopped by Sheriff Jody Mills, who was aware of Clay's undead status, but chastised them for intending to shoot him. Upon hearing about their plan to shoot him, Clay angrily pointed out that he was still a taxpayer.
During their continued investigation, Sam found out first hand that about 5 days after rising, the undead began to turn, starting with a fever, followed by extreme hunger and finally the killing and eating of anyone around them. Clay progressed this way, and with several other zombies finally descended upon Bobby's house and attacked Dean and Bobby. He attempted to kill Dean first, but Dean managed to grab his gun and shoot Clay in the head, killing him. His body was later burned in a pyre alongside the town's other extinguished zombies.