Buried on a Sunday - Batman: Arkham City (2011)

On a dark and stormy night, in the late 19th century, a merchant named Cyrus Gold was murdered and dumped in the swamps near the emerging Gotham City. As the body sunk into the pit, it was exposed to an unusual chemical in the swamp which miraculously reanimated the merchant. He set out wandering the streets of Old Gotham, unable to remember his name and only able to recite the nursery rhyme “Solomon Grundy.”

Seemingly able to cheat death, the undead man, now called Solomon Grundy, was captured and ruthlessly experimented on. Determined to discover what had brought Grundy back to life, it became apparent that the creature was now immortal, due to a combination of the swamp chemicals and the storm that raged on the night of his death.

As the army moved through the condemned Wonder City searching for stragglers, no one expected what lay in Ra's al Ghul's private medical laboratory. For months, Solomon Grundy had been exposed to the Lazarus chemical and then repeatedly electrocuted.

He had died dozens of times, but each time he was brought back for more. While the soldiers debated what he even was, Grundy revived again—and killed everyone nearby.

Mentally broken by his ordeal, he waited at the lab for the doctors to return and murder him again.