During Jump the Shark, Sam and Dean learn of the existence of their half-brother Adam Milligan with Sam using the teachings of his father on Adam after he is attacked by monsters. They also learn that their father had an affair with Adam's mother resulting in him being born on September 24, 1990 and kept it secret so Adam could have a normal life, unlike the boys. At the end, it is revealed that it was a ghoul (that wanted revenge on John for a previous hunt) and impersonating Adam who was killed but Dean saved Sam and the brothers burned Adam's body.