One of the many monsters called forth by the Xilien in their campaign to conquer Earth. Kumonga's genetic structure contains a gene called M-Base, the same gene found in the Xilien and their genetic offspring and what allows the alien invaders to control the monsters.

Bent to the Xiliens' will, Kumonga first attacks a trailer park in Arizona as part of a global-wide assault from the monsters Rodan, Anguirus, King Caesar, Zilla, Kamacuras, and Ebirah. As quickly as Kumonga appeared, though, the creature is teleported away by his alien masters. Using the disappearance of the monsters as a sign of loyalty between the Xilien and humanity, who have yet to learn of the alien invader's true intent, the Xilien move to phase two of their plan as they warn against an incoming star known as Gorath, which is on a collision course with Earth. However, the Xiliens' true intent is quickly discovered, along with their ability to control those that possess the M-Base gene. Their old plan in ruins and their leader now dead, the Xiliens' forgo a more peaceful approach to the invasion and instead unleash a full scale attack combining the might of their own fleet of ships with that of the controlled kaiju. This approach appears successful, until the Gotengo releases Godzilla from his artic prison.

Seeking a rematch with the flying battleship that sealed him away almost 40 years ago, Godzilla chases after the Gotengo, as the Xiliens' send monster after monster to try and defeat the nuclear giant. Finally, Godzilla arrives in New Guinea where he is challenged by Kumonga, who leaps around the King of the Monsters firing webbing at the behemoth. However, Godzilla catches on fast, and instead reacts by grabbing one of the creature's strands of webbing before it can materialize into a net. With the creature's webbing in hand, Godzilla begins to swing the still attached Kumonga around in circles before releasing, sending the giant spider flying off into the distance.