Nolan Sorrento pilots this mech during the Battle of Castle Anorak.
- One of the largest mechs available in the game, Mechagodzilla is near indestructible and has a powerful lightning attack, but is hampered by its slow speed and maneuverability.
- Whenever this incarnation does either its Atomic Breath or Finger Missiles, its optics will glow accordingly. The Finger Missiles have an orange glow, and the Atomic Breath has a blue glow.
- The Finger Missiles are a reference to the 1974 movie, Godzilla vs Mecha-Godzilla, this being one of the mech's abilities.
Mechagodzilla is summoned onto the battlefield, where Aech (piloting The Iron Giant) charged at Sorrento's mech, firing at it with the Giant's Arm Cannon. This attack, however, proved ineffective when Mechagodzilla punched the gunter mech to the ground and blasting her in the back with its Atomic Breath. Then it noticed the Lorean that Parzival and Art3mis were in and smacked the vehicle with its tail. As it comes close to zeroing the two out by crushing them, Daito, piloting Gundam, flew in and intercepted the attack. After a brief but intense battle, Daito changed back to his normal avatar, still gripping onto the massive mech. Mechagodzilla then grabbed the small avatar, and after he shouted "FIRST TO THE EGG!" and flipping the mech off, it incinerated him with a small blast of its Atomic Breath. It then saw Parzival and Shoto running to Castle Anorak. It was close to zeroing them out again, this time with its Finger Missiles, until Aech interupted the attack, causing the missiles to fly out in random directions. After a brief struggle, Aech held Mechagodzilla still, and Art3mis in shooting distance with an M41A Pulse Rifle. She then proceeded to shoot out Mechagodzilla's left optic, revealing Sorrento inside. After Sorrento muttered "Shit. It's her.", she then threw a bomb inside the cockpit. The following detonation proceeded to explode the head of Mechagodzilla and zeroed out Sorrento who soon respawned.
- This design of Mechagodzilla is modeled after the designs of the 1974 Mechagodzilla, 2002's Kiryu, and Legendary Goji from Legendary Pictures' 2014 film.
- While cited as one of the largest mechs in the OASIS, upon its introduction in 2011, this incarnation is the smallest Mechagodzilla in pop culture.
- The Atomic Breath is a reference to the mech's biological counterpart, Godzilla.
- While in the novel of Ready Player One Mechagodzilla fights against Ultraman, in the film (due to licensing issues) the kaiju fights against the Iron Giant and the RX-78-2 Gundam.