So this is a different story, the first crossover I made! I decided to pair these two together because for one, they're two things I love, and two, I feel like Godzilla would find the guppies given that they both live underwater. Kong is here too because why not. This is an idea I've had for a long time, so I'm excited to finally get to do it. I just hope people still look at BG crossover fanfictions lol.

Also, this would take place after the events of GVK, for any Monsterverse people who read this.

Note: "Bubble Guppies", Godzilla and Kong belong to their respective creators, Nick Jr, and Toho. I write this non-profit.

Chapter 1: Daily Life of Two Titans

It was an ordinary day on planet Earth. The sun was shining in a blue sky over the large oceans. Nature was blooming more green than usual. But it always wasn't like this. Over the past 2 decades, monsters have been coexisting with humanity. Since the 1950's monster sightings and attacks have increased, mostly due to increased use of nuclear weapons. 2014, 2019, and 2024 were all years of Titan attacks, including 1973, where a group of people explored Skull Island. Right now, the Earth is kept under watch by a certain Titan.

In South America, a battle is underway currently between two Titans. One of them happens to be the King of the Monsters himself, Godzilla. He is fighting with an unknown Titan for dominance. The creature uses its large tentacles to attack Godzilla, but he manages to grab them, and uses them to launch the other monster away and into an abandoned building. The monster spits out some kind of heat breath at Godzilla, temporarily stunning him, but Godzilla doesn't seem to care, and roars loudly. He charges at the Titan, attacking it with his claws and tail, until he pins it down and stomps on it. He roars at the monster to submit to him, which it does, and wanders away. Tired, Godzilla wanders back into the ocean.

Godzilla is the King of the Monsters, and one of the alpha titans, which means he rules over all other Titans on Earth. It is his job to protect the natural order of Earth, meaning that if something has to be eliminated to help it, he will do it. While humanity has done some pretty awful things, he doesn't see them as threat worthy. While he does attack sometimes, usually it is out of provocation or humans building weapons to kill him or other Titans. He does have respect for one titan, one who helped him defeat a robot copy of himself, but they went their separate ways.

Godzilla swims across the ocean depths, passing by the ocean wildlife and other marine ecosystems. The ocean is his personal playground, and he makes sure everything is normal. Suddenly his belly rumbles, Godzilla is hungry. Luckily, Godzilla is an omnivore, and while he could eat some plants on the surface, he wasn't feeling that today.

Godzilla spots a pod of whales nearby, swimming peacefully. While they haven't done anything to him, that doesn't mean he can't have a quick snack. Having made up his mind, Godzilla swims towards the whale, and grabs them with his claws and rips them apart, one by one. He killed the entire pod of whales, and had a very tasty meal. Godzilla burped and growled.

It was night time, and Godzilla was getting pretty tired, so he decided to go up to the surface to look at the night sky

When he reached the surface, he looked around to see if anything had followed him or was near him. When he was certain there was nothing, he growled and looked up at the night sky, which was clear and full of stars.

Godzilla had rarely seen a clear night sky, due to being underwater for most of the time, so he was amazed by the sky.

Godzilla groaned and made a roar that echoed across the ocean. He was too distracted by the beauty and light of the stars to look around.

Godzilla felt a connection between the stars and an old ally of his. She had helped him in his fight against Ghidorah, to the point that she had given her life to protect him. By doing this, she had given Godzilla special abilities no other member of his species had before. He was still saddened by her death, given the two had known each other for millions of years..

Godzilla dived back into the ocean and continued to swim across the ocean until he had found a great resting spot. He was about to sleep when he felt something, it was a disturbance.

Godzilla got up from his resting spot and started to search the area for this threat. He looked at the surface and underwater for this disturbance, but he couldn't seem to find it.

Godzilla was getting restless. He roared loudly to see if the threat would appear to him, but nothing happened. He roared louder, but nothing happened. He growled angrily, starting to get annoyed by this. He went back into the ocean to see if he could find it.

Godzilla was swimming in the ocean, searching for a disturbance he felt that was a threat to him and the Earth. The problem was, he couldn't find it. Godzilla searched everywhere, from high to low, surface and underwater, but he just could not seem to find where it was.

Suddenly, Godzilla realized something. The threat wasn't coming from the Earth, it was coming from the world that was under ours. He snarled, and headed towards a place only he knew about.

Godzilla found himself at the entrance of another world. It was an entrance to the Hollow Earth. Godzilla roared loudly at the cave, growled at it, and then swam into the vortex inside the cave. If Godzilla has to go into Hollow Earth, then this threat must be serious.

Meanwhile, inside Hollow Earth, it was a place where gravity can invert itself around. There were many different types of plants and animals, very different from what's on the surface, from small yet large crabs to the Warbats. Hollow Earth is a dangerous place not fit for humans, but perfect for large monsters, especially a certain large Titan.

In a field in the Hollow Earth, a Titan not known gets thrown into a rock. It roars back and attacks, knocking its attacker back. The attack pounds its chest and roars. This is Titanus Kong, or just known as Kong. He is the last of his kind, which were killed off by a war with Godzilla, and Skull Crawlers, which even killed his parents. He met humans during WWll, and in 1973, helped humans escape a massive Skull Crawler. He's a tough one, using his strength and intelligence to defeat opponents. Kong has even held his own against Godzilla.

Kong used some rocks to throw at the monster to try to keep his distance, but it swatted them back at him like baseballs. The creature then charged and knocked him back, angering Kong further. The massive ape roared and charged at the monster, which jumped in the air. Kong used this to jump and grab its legs to slam it on the ground. He then proceeds to rip its head off clean, drinking whatever was inside it.

Kong beat his chest while roaring loudly, signaling his victory. Kong was the alpha titan of the Hollow Earth, which meant no other creature dared to stand up to him. The only threat to him was Godzilla, but they made peace after teaming up to defeat Mechagodzilla, a robot copy of Godzilla.

Kong picked up his axe, and wandered off. This axe of his, was made of a Godzilla's dorsal plates. It made it an effective melee weapon, dealing heavy damage and attacks. It could even absorb Godzilla's own atomic breath, making it even more powerful than before.

Much time has passed since that fight, but Kong still remembers it. Even though Godzilla was toying with Kong until the second half at Hong Kong, he still held his own, even roaring back at a roaring Godzilla, making him give Kong a peaceful death.

But that wasn't it. Humans helped Kong wake up and team up with Godzilla to defeat a greater foe: Mechagodzilla, a robot copy of Godzilla used to eliminate him by greedy humans so they can be the apex species again. With the help of some humans, Godzilla and Kong were able to take down Mechagodzilla, and Kong ripped off the head even. After that, they decided to give a truce, and went their separate ways.

Kong had grown much stronger since those events, due to there being more enemies to fight than on Skull Island. But now he was hungry, so Kong decided to go to a nearby lake and grab some fish from under the water.

As he was enjoying his meal, he reminded himself of Jia, a mute and deaf girl from the Iwi tribe, which was wiped out by a storm on Skull Island. Kong had saved her, and they both protected each other and formed a bond. Jia had to leave him due to the Hollow Earth's dangerous environment.

Kong was enjoying seafood when he got a disturbance. It was somewhere near his ancestor's home, which was destroyed by Godzilla. Kong grabbed his axe and headed there immediately. When he eventually got there, he found out that it wasn't like when he was last there. Everything was cleaned up, and the ground glowed a brighter blue.

Kong recognized this, and placed his axe in the same slot as before. Suddenly, the ground started to shake violently. Kong roared loudly across the place, trying to see if anything happens, but nothing did. The shaking stops, leaving the ape confused about what had happened.

The door opened behind him, and at the entrance was him, Godzilla, who wasn't happy one bit. Godzilla roared at Kong, who roared back at him. The two alphas stared each other down like a death match. Kong tried to reason with Godzilla, telling him he didn't do this, but Godzilla wasn't having any of it, and roared at him, ordering Kong to put the axe down. Kong denied this order and held up his axe. Both Titans roared at each other once more, and the battle began.

Kong charged at Godzilla with his axe, but he managed to duck under the attack, and bit Kong at his neck, pushing him around. Kong retaliated by slamming his fist into Godzilla's neck, causing him to let go, giving Kong the chance to whack Godzilla with the axe. Godzilla pushed the axe away from him, leaving him open to his atomic breath.

Kong charged and landed a hard punch to Godzilla's face, and proceeded to land multiple punches on Godzilla, dealing heavy damage. Godzilla tried to use his beam, but Kong wasn't letting him. Godzilla then clawed at Kong, and pushed him back. As he tried to get up, he was hit in the back with Godzilla's atomic breath, who smiled at the hit.

Kong was pissed off now. He charged, but was knocked down and stomped on by Godzilla. Kong then hit Godzilla in his area, making him roar in pain, and Kong pushed him off him. Kong then picked up his axe and landed a hard blow to Godzilla, making him bleed.

Godzilla knew he couldn't get close with that axe, but he thought of another strategy, Godzilla roared and charged Kong. As he was about to hit Godzilla with the axe, Godzilla grabbed it and pulled it away from Kong, and threw it behind him. With no weapon, Kong ran away from the atomic breath, destroying the rocks and boulders on the ground, but it also caused the floor to fill with energy. Kong tried to throw rocks at Godzilla, with some hitting him, stunning him.

Now Godzilla was pissed. He charged the big ape and effortlessly beat Kong down, clawing and tail whipping him. Kong was about to be blasted, but he managed to pick up his axe, and threw it at Godzilla, while also jumping, planning to dunk him dead. The axe absorbed the energy, and as Kong was about to hit him, a large explosion happened, sending both Titans backwards.

Both Kong and Godzilla got up, each hurt badly from their fight, when the room suddenly shaked again. Kong looked down, and roared at Godzilla to look down too, prompting the lizard to look down too. There was some kind of portal forming below them. It forms, sending both monsters falling into the portal.

Kong had fallen into a mountain top, sending him tumbling down and into a field by a city and town. He tried to get up, but fell unconscious. Godzilla meanwhile, was falling, until he landed into an ocean. He woke up quickly, and swam to the surface. He looked around to see where he was, and noticed there were boats all around him. He then noticed they were piloted by crabs, lobsters and snails. He looked down at one of them, growling curiously at them.

"G-G-GIANT MONSTER!" a lobster screamed. Godzilla roared into the air, and swam underwater. His tail destroyed the boat. He needed to find land soon, so he can find out where he even was.

Authors Notes

Well, here's a nice prologue to how Godzilla and Kong ended up here. The next chapter will be about the guppies, one specifically being the main guppy of this story. See if you can guess who! If you want to, feel free to leave a review, and I'll see you next chapter!