Godzilla

Godzilla is a kaiju from the Marvel portion of the Generation 1 continuity family.

Godzilla (ゴジラ Gojira) is a mysterious creature similar to King Kong. Apparently, it is big, green, snorts fire, and is lizard-like.

Fiction

Super-spy agency S.H.I.E.L.D. had encountered Godzilla before. Alerted to trouble in Oregon by Dum Dum, S.H.I.E.L.D. employee Nicholas Fury threatened to quit if it was "that big green, fire-snortin' lizard" again. Prisoner of War!

These stories do not fit into the normal Marvel continuity. See Earthforce for details.

When Superion was running amok in upper New York State under the influence of one of Bombshell's cerebro-shells, reporter Irwin Spoon compared him to Godzilla when the Autobots he encountered told him the Aerialbot combiner was actually one of the "good guys".

Prowl had absolutely no idea what Irwin was referring to. Inside Story!

While guarding Fearswoop, Jolt read a Godzilla comic book. Rising Storm #3

Tunnel Rat refers to Trypticon as "Mechagodzilla", a reference to the iconic enemy of Godzilla. Everybody Hates Metroplex

Godzilla had his own Marvel Comics series in which he was hunted down by Dum Dum.
Given Spoon's statements about movies, it might be the case that, in-universe, the Japanese made a movie about Godzilla's real-life monster rampages—after all the Marvel continuity contains both superheroes and superhero comics—but drawing firm relationships between the Marvelverse, the main US continuity and the Earthforce continuity is problematic at best.
Super-God Masterforce head writer Masumi Kaneda has stated that God Ginrai (ゴッドジンライ) was named so that omitting every other Japanese syllable yields the word Gojira (ゴジラ), the original Japanese name for Godzilla.
There is another Japanese monster movie, Hojoni, as shown in "Kremzeek!"
Around the time Jolt was seen reading a Godzilla comic, IDW Publishing began putting out their own Godzilla series. Coincidence, or product placement?
Godzilla was the direct inspiration for Humungado, right down to his theme music.
"The Champ" has Grimlock mimic Godzilla's infamous sliding tail-kick from Godzilla vs. Megalon.