Disclaimer: I do not own Dragon Ball, or any of its associated characters and lore. That right belongs to Akira Toriyama.
[SMM]
The Saiyan Machine Mutant
[SMM]
East District, Mount Paozu, Planet Earth, Age 749, September 1
With her summer vacation slowly coming to an end, Bulma was even more eager to find all seven Dragon Balls and make a wish before she had to go back to school. After finding her second Dragon Ball not too long ago, Bulma's search led her to the forested part of the Mount Paozu region, where she drove her car very fast in her excitement that she almost ran over a person, who was lucky and athletic enough to successfully dodge her vehicle.
Stopping the car instinctually from the realization that she almost killed a person, Bulma quickly got out to look at her would've been victim in concern before the person in question, a small boy in fact, attacked her car and crushed it with his bare hands. Terrified by what she was seeing, Bulma felt the urge to get her gun, but held back after seeing that her car's destroyer was indeed a kid.
As soon as the boy was done with his destruction, he turned to Bulma with a visible pout and said. "Sorry that I broke your car, but it wasn't nice or safe driving so fast to the point that you nearly ran over us."
While somewhat confused by what the boy said when referencing himself, Bulma nonetheless held her hands up in a placating gesture and said. "I'm sorry, I'll try to be safer and more observant while I'm driving."
It was then that the kid opened his mouth and said in a completely different voice. "Please do so, gorgeous. While I doubt that would've killed Kakarot and me, I don't want to die as unceremoniously as that."
Blinking her eyes even more confused, Bulma shakily asked. "You wouldn't happen to have more than one personality in the same body, right?"
As soon as the kid processed what Bulma said, she could've sworn she heard two laughs for the price of one booming out of his mouth when he toppled over in his hysteria, which creeped her out even more. After calming down, the boy turned to Bulma with a more innocent smile and said. "Why don't we talk more about this at our Grandpa's house, Miss? I'm sure Baby doesn't mind already."
"Uh, Baby is the second voice while you're Kakarot?" Bulma questioned unsurely.
Baby scoffed from Kakarot's body as he dismissively waved the latter's arm and said to Bulma. "Trust me, beautiful, it wasn't my choice of a name, but my creators' instead."
Following the two people in one body to a small hut, Bulma met the martial artist, Gohan, who kindly welcomed her into their home as they each exchanged stories. As Bulma explained her quest for the Dragon Balls, Gohan, Kakarot, and Baby told her of the history of two Humanlike alien races that were endangered, the Saiyans that Kakarot belonged to and the Tuffles that created Baby. Recognizing the Saiyan name from what her alien friend, Jaco, told her about as a little girl, Bulma listened as the two orphaned offworlders explained how they came to join together as one.
"Before my people were completely wiped out by the Saiyans, the King of all Tuffles bonded his DNA with a new type of artificial being known as a Machine Mutant before jettisoning the life form in question, yours truly, into space to one day rebuild the Tuffles and get back at the Saiyans." Baby told Bulma before adding. "After five long years of gathering my wits, I directly the spacecraft I was on back to Planet Plant to see how things were going since my departure, but by the time I arrived in the star system two years later, the one-time homeworld of the Tuffle race alongside it's entire population of Saiyans was destroyed by the Galactic Overlord Frieza."
"That's when I come in." Kakarot then said. "My parents were able to help me escape before Frieza destroyed the planet, and the spaceship I was in collided with Baby's, which led to him hitching a ride."
Baby scoffed as he then added. "I honestly had half a mind to hurt the infant Kakarot when I had the chance, but, well, I didn't." His tone of voice became a bit softer as he said. "I guess it was because a recognized him as another orphan like myself, so we eventually forged a symbiotic relationship by the time we came to Earth."
Kakarot chuckled. "He can be pretty mean, but Baby's not so bad once you get to know him." He then thought of something as he asked Bulma. "Hey, can the Dragon Balls be used to bring dead people back to life?"
Gohan answered for her with a solemn tone as he guessed his reasons. "They actually can, Kakarot, but from what I understand about the legend, is that the Dragon can only revive people who have been dead for about one year, so I'm afraid that you won't be successfully wishing for your parents to come back. I'm sorry."
After a brief sigh of disappointment, Kakarot quickly turned to Bulma with an excited smile as he said. "Can Baby and I still come along on your quest, Bulma? I think it'll be pretty fun."
Baby shrugged from within Kakarot's body as voiced. "It would be nice seeing more of the planet."
Trading a glance with a smiling Gohan, Bulma finally exclaimed with her own smile. "Let's go then, you guys!"
[SMM]
Thought about this on SpaceBattles way back, and it seemed like a promising idea. While I suppose the Baby in canon was a twisted screwball responsible for some wrongs here and there, even before he finally got out of the tank, I can imagine that if the above happened, he could've been somewhat better.