The exercise made her butt grow more.

"You should take a look at your lower region," continued the computer.

Samus looked over at the mirror. To her utter, and delightful, shock, her butt was significantly larger than it had been before she got on the bike. Each cheek was like a yoga ball stuffed into her shorts. Her hips were wide enough to just accommodate them, meaning they could be slightly seen from her front. Here thighs were practically tree trunks. She wouldn't have had room to fit them together if it weren't for her widened hips.

"What the hell? This is fantastic!" Samus immediately grabbed a handful of her cheeks with both hands, kneading and massaging. Her eyes rolled back as she let out a sultry moan. It felt even better than when she first got the upgrade. "My ass is so big and soft..." She explored every inch of her enormously fat ass. It was like kneading dough. "Pear" wasn't the right word for her, anymore. Even "light bulb" seemed inadequate.

"I can't take it anymore. I need release!" She dropped to the ground, hind quarters up in the air, pointed toward the mirror. Resting on her chest and looking back at her reflection, she could see her sopping wet pussy in dire need of attention. She stretched both hands between her legs and started massaging it through the fabric. Moaning the entire time, she began bucking her hips, causing her gigantic butt cheeks to jiggle and clap.

"Oh my god, it's so good!" she cried, edging closer to climax. "My ass is so big! It's phat! It's gigantic! It's the biggest ass I've ever seen, and I love it!" She worked harder on her pussy lips, fingers drenched in her juices. She came once, twice, three times, and she still wanted more. Her prestigious butt turned her on so much. It was like her mind had come to revolve around it. Just seeing it wobble around in the mirror was enough to drive her wild.

She continued like that for an hour, until finally she was too exhausted to move. Her cheeks made a loud PLOP sound as she fell to the side, chest heaving from her heavy breaths. That was the most she had cum ever. Her lips curled into a smile. This upgrade was amazing. She never wanted to remove it.

"Now that you're done, Samus, I need to inform you of something." Samus barely registered the AI's voice, but the part of her brain that was still somewhat reasonable paid enough attention to comprehend what it was saying. "As I was going to say, before you got "distracted", it seems the pear upgrade has also increased the rate in which you gain strength through exercise. While not necessarily a bad effect, it is also causing your lower half to grow in proportion. Fortunately, this means the advantages provided by the upgrade improve. On the other hand, your weight is increasing slightly faster than your strength. If you get too big, you will slow down, and ultimately be unable to move."

"If you'd like, I can attempt to repair the upgrade and remove this unintended effect. You can also simply remove it, though I can't guarantee you'll return completely to your prior state, or you can keep it as is. Another option is to install yet another upgrade, and see if this unexpected effect has any interesting interaction. Of course, these are all just some possibilities. I'm merely here to assist you, you are ultimately the decider of your fate."