Zeus is an Alpha-Class Bio-Android developed by Systems Corp., and one of the three elite bio-weapons created at Genetics Research Building A, the others being Poseidon and Hades. He was deployed alongside Hades to hunt and kill Project 154. He is defeated by the player in Thing-Thing 2.
Unlike Poseidon, Zeus appears to be mostly or completely robotic. His signature weapon is a large rifle (as it appears in Thing-Thing 4, the weapon is almost identical to the Hades Rifle, save for the black barrel) that can pierce multiple targets at once with a single shot.
Zeus is far more difficult to beat than Poseidon - he can deplete a third of the player's life with any attack, and upon nearing him, Zeus knocks the player into the air and shoots at him. During the battle, he jumps around the two platforms that compose the arena. On the top platform, he fires in both directions, making attacking him difficult. In addition, he is aided by Systems Corp. mercenaries, further complicating the battle. He is the only enemy in the game to use a ranged weapon.
- After defeating Zeus in Thing-Thing 2, its head and torso are available for use as a costume.
- During Zeus' death animation, listen carefully when his head explodes, you hear him scream.
- As a matter of fact, that scream comes from Vectorman 2, a run-and-gun platforming video game released for the Sega Genesis video game console in the mid-1990s, which leads to another fact that his boss music (and the sounds he makes when he takes damage) is also from Vectorman 2.
- Zeus is named after the Olympian God of the Sky and Thunder from Greek mythology.
- His rifle (in Thing-Thing 4), along with Hades', used a modified version of the animation model for the FN FAL from Thing-Thing 3.