Baby's unexpected attack forced Goku to transition into a defensive stance. The Saiyan took Baby's introductory jab with a cross-arm block, instantly feeling numbness passing down his body the moment the blow connected. That numbness soon turned to pain and then some uncomfortable cocktail of the two as Goku could visibly judge how much his defensives had lowered after just one blow.
The follow-up uppercut shook Goku to his core, nearly pulling the upper half of his body clean off the lower half and stunning the Saiyan with the unchained weight behind adult Baby's blows. With a sadistic cackle, enjoying his superiority, Baby grabbed Goku's face and dragged him by his whole head, smashing him into the ground before spinning around with a backhand to ground Goku further and make the floor underneath him collapse.
Enveloped in a purple aura, Baby Vegeta took off in a rush, blitzing and vanishing around the debris of the collapsed floor while flashes from the laser bolts of the Machine Mutants waging war on his friends lit up in the background. Goku leaned aside from the incoming blow and drove a fist into Baby's solar plexus, making even the adult Neo Tsufurian blank out in pain for a second.
That little opening was everything that Goku needed, by pushing his entire body behind the blow, he slammed a right step in uppercut into Baby Vegeta's chin before taking off with a spinning whirlwind kick that sent Baby Vegeta flying off. Goku burst with the radiance of his full-powered Super Saiyan and blasted off in pursuit of Baby Vegeta, betting on inflicting as much damage as possible and reducing the difference between his own and his opponent's Ki as much as possible during this momentous opening.
Goku didn't even see Baby Vegeta's arm move. The entire limb of the Neo Tsufurian vanished before driving into the back of Goku's head, nudging the Saiyan's belfry down and forcing his chin to tuck to his chest with a painful twinge to his neck muscles. A kick to Goku's gut bent the Super Saiyan over while a devastating uppercut sent Goku flying off and smashing through pipes, walls, and heavy machinery operating inside of the rebuilt Big Gete Star.
Just this brief exchange left Goku panting and bruised. It didn't take a genius to surmise the extent of how different the powers were here. Given his intensive training, Goku was certain he might have given a good fight to one of Baby Vegeta's forms, which one remained unclear, but it wasn't this adult one for sure. Giving himself the luxury, Goku's eyes wandered off to Gohan, Yamcha, Videl, and Giru who were being constantly terrorized by Machine Mutants. It was as if the entire Big Gete Star came alive and began rebuilding and sending new models back into the fray, merging the obsolete models into even larger and more powerful, more destructive, and better-armed automatons.
The sudden appearance of Baby Vegeta in front of him with a snap made Goku gasp before taking up a frantic defensive stance, but the Neo Tsufurian just cackled and crossed his arms. He was no master martial artist, but it didn't take one to realize that he was in control and could afford to play around with his food a bit.
"You're like a spitting image of that rebellious Saiyan on Earth. Another spawn of his?" Baby Vegeta wondered out loud.
"You're inside Vegeta's body, aren't you? Why don't you consult him?" Goku grumbled before forcing himself out of the hole in the wall he laid trapped in. The jagged wreckage ripped his orange gi into tatters, but Goku wiped the trace of blood off the corner of his lip instead before switching his fighting stance to a balanced one instead of a purely defensive one. If he were to defeat Baby and save his friends from the infinite army that the Big Gete Star was pumping out, defense wouldn't do. He needed to attack and win.
"Hmph… I've long since accepted that Saiyan's mind has nothing worthwhile to say. Even when I relied on it for combat assessment, the ego of that fool kept failing me and supplying me with faulty information!" Baby Vegeta sneered back at the Saiyan. "You, however… I can feel this body being very interested in. It's like my every nerve is lighting up at the same time, itching to punch you over and over again!"
"That's what it feels to be a Saiyan," Goku smiled. "I feel that way about every strong guy I meet. Better get used to it."
"Do you really think I intend to keep this body?" Baby Vegeta scoffed at Goku, belittling his naivety. "I fully intend to abandon it in exchange for Hatchiyack's body when I'm done with you and when I won't be interrupted. Though perhaps I should wear King Vegeta's body while I destroy Planet Earth, as a warning to the universe to never allow the Saiyan population to grow to never again trust them! It will serve as a fine final reminder of the terror that the universe will move past once I exterminate the Saiyans!"
"All that power and you're not even a little excited to test it? You just keep on yapping! I guess I'll have to attack you then!" Goku switched his stance into one suitable for an all-out attack, nothing but openings all around but just the right stance to throw hands and feet with reckless abandon.
"You intend to attack me? Have you not seen the vast difference between our strengths before?" Baby Vegeta jeered at Goku while the Super Saiyan crossed his arms and tilted them over his head. Goku spread his legs wider, at least around the level of his shoulders. His body, which had previously utterly absorbed the Super Saiyan aura, began releasing it with its full splendor, drastically boosting the power output of the body but also the wear that the form put on it as well.
"You're right, if I am to defeat you, I'll need to gamble everything! To use a hidden ace that I've been polishing for some time now. A technique entrusted to me by King Kai in combination with Super Saiyan! Super King Kai's Fist!" Goku declared, bringing his arms down and igniting a crimson aura around him and giving his body and spiky Super Saiyan hair an intense red hue as well. "I hadn't perfected this combo yet, so the strain on my body is almost the same as cranking the King Kai's Fist to this level of power naturally, but I won't beat you without this all-or-nothing gamble!"
Goku took off like a speeding comet, crashing into Baby Vegeta with a flying punch and denting his cheek fully before the inertia caught up to Baby Vegeta and sent him packing. Not feeling content with just this much beatdown during his one heartbeat of pure opportunity, Goku exploded with the crimson aura of King Kai's Fist again and crashed into Baby Vegeta with a jab, a roundhouse kick, and a double ax handle slam to ground Baby Vegeta in a crater through the floor.
"More and more rummage in the way of the resurrection of the Tsufurian race! How will you mask your bigotry, I wonder?" Baby hissed, pulling himself out of the massive jarring hole in the floor before Goku, still enveloped in Super King Kai's Fist aura, appeared before him with a cold expression sealed on his face.
"I don't care about any of that. I just want to defeat you!" Goku exclaimed, extending his open palm and sending Baby Vegeta flying with a fierce Kiai pulse. Catching up to Baby in mid-air, Goku delivered a vicious and thorough beatdown before knocking Baby Vegeta away, appearing behind him to thrust his feet into Baby's back and send him into the air, then appear over Baby Vegeta's head to hammer him back down, only to appear right where Baby Vegeta would've crash-landed in to thrust both his arms out and unleash a furious Kamehameha wave out of nowhere that washed over Baby Vegeta and carried him off through an entire country worth of laboratories, rooms, and wreckage before obliterating all of them in the resulting explosion and leaving a smoking hole in the Big Gete Star.
Goku's arms weighed down, demanding that he would surrender his whole body after them. Shaking and swelling with tension in his muscles, Goku maintained his stance while staring off into the distance and at the blazing and smoldering trail of destruction that his explosive power left behind. Even his Super Saiyan splendor snuffed away with Goku, wincing in pain and clutching his aching right peck.
"As I thought, the strain is out of this world! King Kai's Fist and Super Saiyan weren't meant to be used together. But this is the only way I can pull it off… I should be able to pull off one or two more bursts if I keep it at around King Kai Fist x2," Goku tried reasoning with his own body before feeling the tiny beacon of hope brimming inside of him. That beacon of spare strength that he could squeeze out of all it was worth helped Goku to ascend back to Super Saiyan. Baby Vegeta's Ki was still there, and it was as strong as ever. Honestly, it was a little disparaging even for someone like Goku to hit this guy with everything he had and only see dirt and bruises on him when Baby Vegeta returned to the battlefield.
"Loathsome Saiyans!" Baby Vegeta hissed, clenching his fists so hard that they shook from tension. "Even when I have reached my Adult Stage, complete perfection in terms of development of this artificial Neo Tsufurian body, when I'm inhabiting the body of the strongest in the universe, still… Still, you somehow manage to wound me!"
"That's what you still haven't understood about us," Goku smirked. "Just because you've taken the body of the strongest in the universe doesn't mean someone else can't surpass them! All of us are martial artists, all of us are rivals, so it's only natural that one of us discovers heights no one else has ascended to before. If you rely on pointless titles like "Strongest in the Universe" and stop improving, you're bound to be overtaken and left behind!"
"Not by you…" Baby Vegeta closed his eyes, gnashing his teeth. "I refuse to be beaten, to be injured by someone like you!"
"Now you sound a lot like Vegeta…" Goku teased Baby Vegeta before the pair took off at one another. Colliding at a middle point in the air and erupting with a cascade of invisible concussive collisions that raised hell and burst with supersonic booms and flaring light shows while causing violent short-outs in the surrounding laboratories, halls, and engine rooms.
The two appeared spontaneously at a random location on the Big Gete Star, only to exchange flurries of blows and kicks before perfectly blocking and deflecting their opponent's blows, then vanishing again, only to appear at another location. The atmosphere became literally electric with rumbling electric crackles accompanying each successive collision that sent an expansive shockwave in all directions.
Goku thrust his elbow into Baby Vegeta's gut, tripped his legs with a sweep before unleashing a split-instant point-blank Kamehameha wave only for Baby to block it and vanish with the Super Saiyan vanishing immediately after. When the two next appeared within the scope of sensory, Baby tripped Goku with a hooking sweep of his right arm before snap-vanishing away and appearing above and behind the Super Saiyan only to crash down into his spine with an elbow. Goku thrust his palms out to block the following knee strike and then blocked the incoming double ax handle slam before the two began frantically exchanging blows and vanishing all over the place.
The two became two vertical thunderbolts, red and purple, moving parallel to one another and sharing the incomparable surge between each other in the form of swift yet potent blows yet neither side gave way to the other with the two humoring their respective opponent by keeping up their part in this mad dance of violence and martial arts. It was only when the two collided up top with slamming elbows and down low with shooting knees and found neither to push the other away that the pair rolled back into place, making some space between each other.
"I was going to ask you to stop holding back and delve into Vegeta's fighting instincts again, but it's like you're advancing your martial arts prowess by ten years' worth of training with every punch you throw. Honestly, it's a little humbling…" Goku snickered in excitement, still working through the pain resonating through his entire body after that intense exchange.
"Of course! I have no need to rely on a Saiyan's experience of killing innocent, defenseless civilians. I possess the peak of Tsufurian artificial processing power and the sum of all of our collective intelligence. If anything, praise yourself for defying any sort of logic or reasoning in matching my pace beat to beat while so hopelessly outmatched in terms of power!" Baby Vegeta hissed back. "I thought you had to rely on that King Kai's Fist technique that three-eyed Earthling used against me to match me, but you seemed to hold out just fine without it too."
"Actually, I've been using it this whole time," Goku laughed out with boundless cheer in his look while apologetically rubbing the back of his head. "There's no chance of me catching up otherwise, just like you said. Though it's just barely enough to catch up while burning through my whole body, even when I'm using it. I'm sorry, body… You'll just have to hold on for me. I've exhausted my two safe uses of Super King Kai's Fist."
"So, what are you going to do now that you're all tuckered out?" Baby Vegeta wondered with a confident smirk on his face. "You're giving this Adult State quite the fight, are you saying that you're throwing it?"
"Not a chance!" Goku smirked. "You're giving me a fight of my life! Since I've used out both of my Super King Kai's Fists, I'll just need to crank it up and push through! Super King Kai's Fist x3!"
"Wait, what!? B-But didn't you say you can only use that power-up twice and only up to x2?" Baby Vegeta gasped in confusion.
"That's the thing about us martial artists, when we hit a wall, we PUSH THROUGH IT!" Goku roared while exploding with an even more powerful and rowdy crimson aura that granted his body and spiky golden hair a crimson hue. "Even if my body breaks down completely! I'm giving you all I've got AND THEN SOME!"
Super Baby Vegeta didn't even see Goku move. He only became aware that his opponent was attacking when everything went white and he began feeling weightless. It was Goku's elbow that decked Baby first, hurling him backward and bending his spine to an uncomfortable degree. A kick to the shins tripped Baby Vegeta up before a flying triplet of roundhouses finished up with a thrusting kick to Baby Vegeta's gut bent him over.
"Ka… Me…" Goku drew his arms back. While stunned and numb, Baby collapsed on the floor, still riding his heartbeat of limitless power, Goku ascended into the air and formed a strident azure energy sphere in between his hands that radiated with all-consuming white light. "Ha… Me… Ha!" Goku thrust his arms forward, releasing a thick and uncompromising Super Kamehameha wave that slammed against Baby Vegeta's floored body like the stream of a waterfall, forcing his way through the floor and into a dark engine room which ended up completely obliterated, blazing, and drowned in smoke after the resulting explosion.
Goku's arms lingered raised in the air while the entire cosmic structure around him shook and sprinkled bolts and shrapnel, systems shorted out, turned off, and exploded unable to maintain their functionality. The King Kai's Fist aura vanished almost at the same time as Goku's Super Saiyan luster, reducing him to a bruised and tattered, swollen, and panting state.
"It beggars belief… After all the limitless advancement, my constant maturity, and evolution, there is still someone powerful enough to draw my blood," Baby Vegeta emerged from the failing engine room busted up, having taken some rips and tears to his tight black bodysuit and some bloody scrapes on his eyebrow and lip. "To think that I sought compromise, that I thought a peaceful resolution was possible with the Saiyans. Dr. Lychee knew best. I was arrogant to think that with all the collective Tsufurian knowledge, the peerless processing brainpower of the most advanced computer chips in the universe, and a perfect artificial body it made me know any better. Someone this powerful, this violent, and this dangerous… Simply cannot be left alive!"
"I won't let you kill anyone!" Goku cried out, bursting with the golden Super Saiyan aura and igniting the crimson Super King Kai's Fist again for just a blink, unleashing another Kamehameha wave to push Super Baby Vegeta back into the same crater he lifted himself from. Bellowing from the collection of both pain and the unbearable surge of his own power, Goku amplified his energy wave with an additional pulse of Ki, forcing Baby Vegeta even deeper down and causing an even more violent explosion.
After the smoke cleared, Baby Vegeta ascended from the crater with the tears on his bodysuit having multiplied and the few he had collected having deepened, however, ultimately unharmed. As Goku's Super King Kai's Fist aura and then Super Saiyan luster vanished, the Saiyan was left stunned at the lack of sting that his signature attack had left on his opponent's body even after powering it up to the max.
"Your attacks don't pack the wallop they used to, Saiyan. Could it be that all your reckless pursuits of power against opponents you have no right to stand against have finally caught up to your feeble, simian body?" Baby Vegeta bit at Goku while sneering at him with a judgmental and rotten stare from down below.