Jackenstein is a boss enemy of Sir Hammerlock's Big Game Hunt. It is a monstrous creation of Professor Nakayama that appears in the Sunken Cargo Room of the H.S.S. Terminus at the end of the campaign.
Professor Nakayama has set out to revive his idol, Handsome Jack, and in order to protect his work he has created this most obscene of creatures to guard him in the H.S.S. Terminus. Jackenstein is a fusion of Pandoran fauna, further reinforced by Hyperion implants and robotics, left to defend against any attempt to access Nakayama's precious laboratory.
- Main article: The Fall of Nakayama
- Jackenstein has a chance to drop the Yellow Jacket SMG.
- Jackenstein's capacitors are immune to all forms of elemental damage, including explosive damage.
- A successful shot on Jackenstein's transformers will always score a critical hit.