A self insert with the powers of GODZILLA.
"Just imagine all of Godzilla's strength, speed, durability, senses , regeneration, radiation absorption and manipulation, and atomic breath compacted into a human"
Other than some absurd cosmic level beings or reality manipulators , this human/Godzilla si will steamroll through everybody, in any settings.
And that's just Monsterverse Godzilla.
If the si somehow is able to scale himself upto Godzilla Earth level, Even cosmic level beings will have a very hard time trying to put him down.
It could be a an awesome wish fulfilment kinda fic.
Especially a Worm fic.