Jace awoke the next day.
He lifted himself out of bed and walked over to his ladder. He placed one foot on it, then the next. He made his way to the top. The ladder was creaking more and more every day, he felt if he wasn’t careful would’ve easily broken one. He noticed his sister wasn’t making breakfast yet, he looked out the windows, it was the morning. He check the clock on the wall. She should’ve been up by now.
He shrugged it off, she probably stayed up a little too late, she isn’t used to being up late. He walked into the bathroom and looked into the mirror as usual.
“Holy shit!” He said to himself.
He was huge. His arms were nearly double the size of yesterday. His shirt was so tight on his muscles. His pecks were giant, his abs were rock hard, he had more than 6 now. His shoulders were incredibly wide. He looked at his legs. His shorts couldn’t stand a chance. He looked at his face too, his hair was now a medium sized afro. His face, his beard. He had a really furry beard. It was thick and dark. He couldn’t believe it. He not only was more muscular, but he was undeniably older by now. He was 16 a couple days ago and by looking at himself he looked 18 or 19. He was taller too. Before he was 5’9, now he was 6’3. He knew he had to have a shower, and this shirt barely stood a chance so he risked it. He flexed his arms, the shirt tore instantly. It was oddly arousing. He realised he was getting a little hard. He looked into the mirror at his crotch. As it got harder, his shorts were losing the battle. They broke, falling to the ground. He was left in his underwear and a shirt with ripped arms. He took off the shirt and underwear and took a shower. There was a lot more to wash now, he noticed.
He got out the shower after he was finished, he picked up his underwear and slid it on after a lot of effort. They still fit semi well, excluding the fact that his bulge was outlined perfectly. His large balls were shown through, too. He grabbed his shirt and pulled it over his head. It didn’t make it past the shoulders before it ripped in two.
Jace opened the door quietly, trying not to bring attention to himself, he looked around. His sister wasn’t out of her room yet. He carefully got to the ladder and got himself down as quickly as possible. As he did. On the 4th step, he accident snapped it. Their caused him to slip. He really was heavy, now. He got himself to his room more carefully. He opened his drawer and looked for clothes that might fit. He found a tank top he’d ordered a year ago. He accidentally ordered it a extra large. It was still tight on him. But it worked. He looked for something to wear down below. Nothing seemed to work. He looked for the largest pair of underwear he could. It still outlined his bulge but to a lesser extent. He looked for some pants that weren’t too tight. He found some fairly loose pants, they wrapped around his thighs and calves, but he could fit them and they didn’t make his dick look too big. So he went with them. His arms were showing, his sister would absolutely notice them. So he tried to find a jacket or something. Bingo! He found a hoodie that his friend’s dad bought him at an event that was too big for him.
He looked much more normal. He couldn’t hide his much larger feet or increased height. But he was sure Blue wouldn’t question it.
He made his way up the ladder, as carefully as he could. Jace poked his head up. Blue still wasn’t out of her room. He was a tiny bit worried.
He made his way to her room, he knocked on her door,
“Huh!?” A familiar voice yelped out of surprise. The door unlocked itself and opened, her head poked out, just her head, none of her body. She looked at Jace, up and down. Then she looked at his face, “Uh, Jace, I’m not feeling too well right now, I don’t really wanna come out right now,”
“Blue...” Jace said, more concerned, less preoccupied with his body, “are you sure you’re okay?”
“Yeah, I’m fine, don’t worry,”
“Okay...” he said, “you seem more off that when you’re usually sick. I mean whenever you’re sick you usually persist throughout the day,”
“Yeah... well... today is...” she stopped to think, “okay. Listen, I know what I said yesterday was a joke but I am actually starting to get worried now,”
“Huh?” Jace started sweating a little,
“Just look,” she opened the door wide and stood in front of Jace.
She was wearing her regular tank top, her jeans were barely up her thighs wearing blue boxers.
Her thighs were undeniably thicker than yesterday. Her hips were in line with her shoulders now, he could only imagine how big her butt was. He looked at her waist, it was as thin as always, but paired with her hips, she had an hourglass look to her. Her chest, her boobs. Yesterday they were only a little bigger than before. They must’ve been 2 or 3 sizes bigger now.
“Just look!” She said, turning to the side. Her butt was twice as big as yesterday, sticking out like a shelf. Her boobs were much bigger than before. She grabbed them and felt them, “they’re so much bigger, I don’t know how this happened,” she said, she let go of them, they bounced as they fell. She looked at Jace, “this can’t be a coincidence. I mean look at you,” she forwards towards Jace’s to grab his bicep.
For the first time in Jace’s life he saw his sisters cleavage.
He then heard a snap, her bra fell down her top. Her top wasn’t the most opaque of tank tops. It fell and it watched it through her top. Jace had seen his sisters nipples through her tank top before, and they absolutely looked bigger. Not by a lot, but they looked bigger, they tented the top too.
“Shit,” she said, “that’s the second one today. I only have 2 bras.”
“Uh,”
“You don’t have to say anything, I know you’re as confused as me. Just hope that we don’t get any bigger okay...”
“Y-yeah,”
“And I’ll find out who did this, or why this is happening and I will beat the shit out of them,”
“Uh...” Jace was worrying now,
“And... Jace?” She looked him in the eyes, he was worried, super worried she’d figured it out, “you don’t mind if I don’t wear a bra for the rest of the day, right?”
He let out a sigh of relief, before quickly going, “yeah yeah, of course. Whatever works,”
“Okay, good,” she smiled, she was surprisingly calm for the situation.
The day went out fairly regularly. Jace stayed upstairs today, he watched as his sister would grab her boobs to see what they were like. He heard her moan one time. He had to pretend like he didn’t hear it. He was pretty sure she bought it.
Her boobs were so much bigger from her nearly nonexistent breasts a few days ago. He watched as whenever she walked, they bounced around. Her ass was bigger too. So much bigger. It was a real challenge not to be turned on by his sister but he managed to succeed.
At one point Jace was caught looking at her butt,
“What you looking at, muscle boy,” she joked,
Jace quickly replied, “just looking at what Casey’s missing out on,”
Blue suddenly went red, “hah...” she said, she started laughing, “you got me with that one. Stop being such a smartass,” she continued to laugh. ‘Good save,’ Jace thought to himself.
He felt like he was a good brother... then again. This was all his fault.