He's Godzilla, but a Skeleton. Simple.
Skeleton Godzilla was the original Godzilla, then he got killed by the Oxygen Destroyer.
Becoming a Cyborg
Go watch Godzilla Against Mechagodzilla and Tokyo SOS.
Being recruited by Death T-Rex
Death T-Rex sensed a being in Universe 986 that was both living and dead. That being was Kiryu. since he was in the market for minions, Death T-Rex ripped the Skeleton out of Kiryu and reaniated it as Skeleton Godzilla.
A T-Rex Halloween
Skeleton Godzilla, as well as Death T-Rex's other minions, were teleported to the spooky graveyard to fight T-Rex and his friends. Skeleton Godzilla tagged team with SkeleT-Rex for a little bit before Godzilla showed up. After defeating Shin Ghost Godzilla, Godzilla transformed into Super Super Godzilla and defeated Skeleton Godzilla with a single falcon punch. After the battle, the GDF took back the skeleton and rebuilt Kiryu.
Skeleton Godzilla appears in the third episode of the series, once more in the thrall of Death T-Rex.
When T-Rex and co. called for an Uber to take them home, the driver of said uber was revealed to be none other than Skeleton Godzilla. However, following this revelation, Skeleton Godzilla was quickly defeated by Godzilla and T-Rex.
- Ghostly Atomic Breath. This beam is white, like the original Godzilla's.
- Skeleton Godzilla is my second Skeletal Kaiju, after SkeleT-Rex.
- Skeleton Godzilla parodies an old fandom misconception that Godzilla's skeleton was an accurate depiction of Ghost Godzilla
- No spook scary skeleton jokes, I already beat everyone to it.