My Little Sister, Amy Chapter 5 [Webtoon]

An eager younger sister convinces her brother to undergo a scientific experiment that will turn him into a beautiful girl, and he reluctantly agrees. When the spell activates, his shirt strains against sudden curves and he shouts that the transformation is accelerating beyond his control, unable to resist. Stunned and barefoot on the floor, he realizes the change occurred in an instant, leaving his sister to mock his new form.