As his sisters opened their eyes and looked around, Cory couldn't help but feel that this situation was unfair - it was Katie's fault that the shrink ray went off, and she was the only one who hadn't been shrunk. The youngest sister giggled with glee as she picked up all her shrunken siblings, holding Cory and Maddie in her left hand and Gabby in her right, and held them up to her face.
"Looks like I get to be the big sister now," Katie proclaimed. She then got up off the couch with a smile on her face and started walking towards her room, slowly lowering her tiny siblings until they were level with her chest. Knowing how jealous Katie was of her sisters' larger breasts, Cory figured that she must be pleased with how big hers seemed to the little people in her hands and that part of her wanted to rub it in her sisters' faces.
"Wait, you forgot the shrink ray!" Maddie yelled as Katie reached the bottom of the stairs. "And the notebook!" The youngest sister, however, ignored her as she went up the stairs and reached her bedroom door.
"Listen to your big sister," Cory pleaded as Katie opened the door and went into her bedroom. Although he knew that he, Maddie, and Gabby were going to be stuck at their small size for the whole day, he hoped that his giant sister would at least take the time to learn about how exactly being shrunk worked.
"Big sister?" Katie teased. "I only see two itty bitty little sisters and one itty bitty little brother!" She then dropped her three shrunken siblings onto her bed. They all screamed as they fell and bounced on the mattress. When they looked up at the giantess they were trapped with, she had turned around and was slowly going to sit on her bed - or, more precisely, on them! They screamed even louder as they begged Katie not to squish them under her butt as it got closer and closer to them. Fortunately, her giant butt stopped descending before it even touched any of the small siblings below.
"Does this skirt make my butt look big?" Katie asked as she playfully shook her rear from side to side a little and gave it a smack before turning around and kneeling to speak to her shrunken siblings. "Or are you too busy staring at my tits?" she added, pressing her boobs together to make them look bigger, even though each one was already bigger than the people she was addressing.
"Fucking hell, Katie," Gabby scolded, still panting heavily from shock, "you almost killed us! If you're not gonna be careful with us, you need to go get the shrink ray and the notebook and unshrink us now!"
"Um, actually ..." Cory tried to interject to mention that, with the shrink ray being at critically low power, there was no chance of anyone being returned to normal size before the end of the day.
"Yeah," Maddie interrupted, trying to catch her breath, "what would mom think if she found out you zapped us with her old shrink ray and then killed us?"
"Fine," Katie huffed with a scowl on her face, "I'll be more careful, and I'll go get the shrink ray and the notebook just in case." She turned around and stomped out of her room, leaving the tiny siblings on her bed.
"Her butt did look pretty big, didn't it?" Cory jested, trying to lighten the mood. Sadly, if the glares he got from his sisters were anything to go by, his joke went over like a lead balloon.
Katie returned a minute later with the shrink ray in one hand and the notebook in the other. She put the former on her dresser and brought the latter over to her shrunken siblings, who noted that she seemed quite pleased about something.
"So I was reading this," Katie explained as she took a seat on her bed next to her siblings, "and it said that you can't be killed or injured in any way while you're shrunk. So I could've sat on you and you'd have been perfectly fine!"
"That would've been good to know two minutes ago!" Gabby snapped.
"And you know what else?" Katie continued as she leaned back against the wall and rolled the bottom of her tank top up, exposing the entirety of her belly. "It said if I eat you guys, you basically become living fat on my body until I use this special 'un-digest' setting the shrink ray has." She then looked directly at Gabby and licked her lips hungrily. "Doesn't that sound like fun?" Katie asked with a sweet grin on her face that made the shrunken siblings glance anxiously at each other. "Although the shrink ray's gonna need to charge for 12 hours before I can use that 'un-digest' setting," she added with a nonchalant shrug.
While Cory already knew about that last part, the news left Maddie shaking and caused the colour to drain from Gabby's face. Not only were they going to have to spend the entire day being tiny, but they might also have to spend the day being sentient fat on their giant sister's body. Gabby was particularly worried about suffering that fate given the way Katie was continuing to look at her like a tasty little piece of meat.
"You gotta get Katie's mind off of eating me!" Gabby begged her fellow tiny siblings. "Come on, you guys, think of something!" The three of them then saw Katie's giant hand descending towards the eldest sister, getting ready to pick her up. Cory desperately racked his brain trying to think of what to say to distract Katie from turning Gabby into a snack.