Fan CastingBatman: Arkham Origins

Description of Solomon Grundy:

Grundy later somehow entered Blackgate Prison's sewer system underneath the Industrial Complex of the facility. Batman, when he tried to track down Black Mask to the Generator Room, encountered Grundy, who prevented a gate from coming down. After he was forced into a battle with the undead super-villain, Batman managed to outsmart Grundy by exploiting the environment to get him electrocuted enough to stun him with Batman finishing him off with several blows, which destroyed the gate in the process. It should be noted that Batman called Grundy by name when he saw him, which either meant that he had encountered Grundy before or was at least aware of his existence.