Blecker x Dragonball

Wonder! The amazing train that fies though space!

Everyone, including Goku, was in the dining car, enjoying a big meal. Cross's food was in a bowl on the floor so that the tiger cub could eat it more easily, though the team did admit it made her seem less human. Puar, despite not having the same shapeshifting limits as Cross, was also in beast form on the floor, enjoying a meal in a bowl in camaraderie.
"So after you're finished eating, you can get back to your normal form and into the training room?" Goku asked.
Cross sighed. "I can get back to my human size, but to get back to my giant size, I'm gonna need about half a day's rest. While I can double my mass as an instant action, going beyond that requires recovery time even with a meal. Sadly, the reverse is not true. I can shrink down to the size of an insect in an instant and be fine, but it can take me nearly a month to get back to normal size after."
"You've gone smaller than this?" Yamcha asked curiously.
Cross nodded. "When we were first exploring the limit of my abilities, I shrank myself down to the size of an insect. Unfortunately, when I tried to grow back up, I ran into a wall, and we spent the next month just incrementally increasing my size to various insect, rat, cat, and other forms as I worked my way back up to my normal human size. I can double my mass once, hold it for about an hour, but then I need to either eat or rest before going further."
Cross chuckled. "We never did find my upper or lower bounds for obvious reasons."
Goku naturally asked what they were.
Cross laughed a deep belly laugh. "Once you go smaller than a bee, it gets a little bit harder to track, and I was scared I might just shrink myself out of existence. Meanwhile, growing big has a different problem: food requirements and space."
"So in theory, could you turn into a form as big as Vegeta's giant ape?" Krillin asked.
Cross nodded. "Or even bigger if I had enough prep time and enough food. Like I said, we've never explored my upper limits, just the time restraints."
The group nodded. Bulma cut in, "At this rate, we'll be in Namek in no time, but do you guys feel strong enough?"
The party all gave a collective sigh.
Cross purred and raised her head. "We just need to get the Dragon Balls within a year, right? That's the limit to reviving someone like Tien."
The group nodded.
Cross purred. "I'll show you how to use the space map function after I'm done eating, and we'll find some breathable planets to pit stop on along the way. Give us a chance to rest and reset a bit."
Korin smiled. "That is a great idea, Cross. Training without rest is a fool's errand. Rest is just as important as power."
The party all nodded in agreement.
"I'm actually surprised Cross was able to convince you and Yajirobe to join us," Goku mused.
"Yeah, well, Cross said there was free food as long as I tagged along to keep you guys safe," Yajirobe replied.
Korin laughed. "She promised something similar for me. She wanted to study my beans and find a way to increase their yield and promised that I could have all the food I want on her ship, so here I am helping you guys."
Puar was next. "If not for Cross, those Saibamen could have killed Yamcha. I won't let that happen ever again."
Chiaotzu nodded. "I lost Tien because I wasn't strong enough to help him. I won't let that happen again either."
Cross looked to Chi-Chi and Gohan. "When you're done, why don't you head up to the lead car? We can start studying about space there."

Chi-Chi was naturally excited that her son was going to get an education. Gohan was equally excited to learn more about the mysteries of space.
Once the meal was finished, Cross took a moment to stretch and shifted to her hybrid form, just at her human size, keeping it "family friendly" as she pulled a rainbow-trimmed white cloak from some storage to throw over her. She led Bulma, Chi-Chi, and Gohan to the lead car, the latter two pausing to stare into the void of space through a window.
Bulma traced her fingers on the glass. "It doesn't even seem that thick, and yet that's space out there, and it's not even cold in here."
"Airs a bit stale," Chi-Chi remarked, "but no worse than an Earth train."
Cross purred. "The Rainbow Line prides itself on top-quality service. We are, after all, transporting passengers not just across a country but the infinity of space and time. Comfort is key."
"It's so cool," Gohan glowed.
Cross purred, leading them deeper, past the passenger areas and into the control room. Bulma smiled, knowing what was coming next, and opened the side door to the void of space as Chi-Chi and Gohan braced for the vacuum, but it never came.
"You have all been staying in the tail car because the gravity rooms are attached to it, but the full train goes much longer, and to move between cars requires stepping outside."
She spun as she danced out onto the railing, standing in open space. Cross purred as she pulled Gohan with her.
"The train produces a zone of habitability around the exterior for moving between cars or repairs, but what's really special..."
She paused as she reached a paw to Chi-Chi, pulling her out into the open wonder of space.
"The view," Chi-Chi gave a soft gasp, the wonder of space taking her breath away.
The four just stood there, in open space, for a good minute in silent wonder. Even Bulma was in soft awe, even though this was not her first time.
"You ever imagine you would be able to see space like this?" she sighed. "I wish I could fly like you, Gohan."
He smiled and hovered up behind her, arms under hers as he lifted her up.
"Be careful, Gohan!" Chi-Chi called, turning to Cross. "How far can they go out?"
"About a dozen feet, but don't worry, it's a gradual fall-off. He'll feel it getting harder instead of just hitting the vacuum."
Chi-Chi watched Bulma and Gohan fly around the nose of the ship and looked to Cross. "Can you take me out there too?"
Cross purred, taking off her cloak and tying it around her waist. Her form shifted into a harpy, head of an eagle, body covered in "family friendly" feathers, her breasts gone. With a flap, she lifted up as she wrapped her taloned feet around Chi-Chi's arms and gave her a tour of the train, flying toward the lion lead car. "Gohan, follow me!"
He nodded and, with Bulma in his grip, followed. The girls' hearts raced with excitement at the sights until they landed and entered the lead door, Cross shifting back to her tiger hybrid form.
"We were in space, real space!"
"That was amazing!"
Cross smiled. "Feel free to do it any time you want. You'll find each car has special areas beyond just the living and dining areas."
She moved to a console and brought up a hologram of their area of space, showing Gohan and Bulma the settings. "Eagle has the sensors, Panda has my workshop, Wildcat is attached to the gravity room but also has the supply room, Crocodile is the armory, and Lion is where Poppy is stored."
"Poppy?"
"A standard issue Rainbow Line stewardess robot, designation Navi Poppins."
Bulma and Gohan were just overflowing with joy.

Chi-Chi pulled Cross to the side, tears in her eyes, "Thank you Cross...it's incredible."

She purrs.