Katie looked up at Rebecca, horrified.
Her sister had become a power mad 20-foot hyper-muscled, well-endowed behemoth!
Katie backed away from her sister with fear. She fell over backwards, backing away on her ass up to the wall as her monster of a sister turned her looming form around to stare at her over her nearly van-sized tits.
Her giga-sized body seemed to go on forever. Chants for 'more power' and hungry cries were all that could be heard. As Rebecca knelt down - cracking the ground all around her - her huge tits bounced and knocked Katie out cold.
"Pfft! Oh well. She couldn't handle this power anyway. She can keep my wonderful pills safe while I go and have my fun," said Rebecca down to her sister's unconscious body.