Pastor Jacob Karns, also known as the Hook Man, is the titular main antagonist of the Supernatural episode of the same name.
In 1862 a preacher named Jacob Karns was angry over the red light district in town on the Nine Mile Road and killed 13 prostitutes. It was written that “some of the deceased were found in their bed, sheets soaked with blood. Others suspended upside down from the limbs of trees as a warning against sins of the flesh.” He was arrested and then executed.
It appears Jacob Karns' spirit fed off repressed emotions. In 1932 a clergyman was arrested for murder and in 1967 a seminarian killed some hippies. In all these cases, the killers had either been influenced or possessed by Jacob Karns' vengeful ghost. In the current case, Lori Sorenson's feelings about her boyfriend, room-mate, and adulterous father incited Karns to attack them.
Dean found Karns' corpse at the Old North Cemetery in an unmarked grave he identified because it has Karns' cross symbol on it. This failed to stop Karns, and the boys realized the spirit still manifested because the silver that made up Jacob's hook was remolded into items in the church. They quickly started burning all of these, but Karns attacked Lori herself due to her guilt over the deaths he caused. They realized that they missed something and realized that Lori's silver cross was made from Karns' hook as well. Once Dean melted the cross, Karns was put to rest.