Over a century ago, murderer Cyrus Gold sought to escape justice by hiding in Slaughter Swamp, where he met a fate worse than death. Mysterious forces doomed the now immortal Solomon Grundy to an endless cycle of death and rebirth.
Batman has encountered him twice in his crime-fighting career, during the events of the Blackgate Riots and during Arkham City. In later years, he became one of Penguin's secret weapons and a way to fatally punish minions.