Lance LaCroix was the husband of Bunny LaCroix.
At some unknown point in time, Lance married Bunny and together they lived in a large mansion.
The marriage was not a happy one due to Bunny's infidelity. They presumably argued a lot as Lance was known to accuse Bunny of sneaking off to be with other men.
Bunny eventually fell pregnant with one of her lovers, and gave birth to a child named Olivia. At the hospital, Bunny intended to pass the child off as Lance's, but when the family got home, Olivia's real father, a shapeshifter, intended to claim the child.
Lance got into a fight with the monster, and was easily killed by him. Lance's death was avenged by Bobby Singer, who came and killed the shapshifter.
Bunny lied about losing the child to her relatives, so she could keep Olivia safe and locked up in the attic, as promised to Bobby, who chose to spare her. Years later, after Bunny's death, Olivia took on Lance's appearance and killed Bunny's brother Stanton, for his outspoken behavior. The witness, Amber, told the family what she saw, leading Sam and Dean Winchester to suspect Lance had returned as a ghost.