Kusuri Yakuzen asked you to try out a shrinking drug she was working on. To say it was a success would be an understatement. (Ignore the voice. I was trying to make it sound like her older self but I couldn't seem to get it right)

You were walking through the woods when suddenly, you encountered a witch. The moment she laid eyes on you, she cast a spell that causes you to shrink down to the size of a small insect.

After being left in critical condition by an attempt on his life courtesy of Starscream, Megatron's spark was removed and placed in a Pretender shell. A female Pretender shell. You are the Decepticon doctor/scientist that was in charge of saving Megatron's life. Now would be a good time to break the news to him before he starts using his new body to turn you into scrap.

One day, while walking back home from work/school/some other event that requires you to leave the house, you come across a girl wearing nothing but a red bikini. She is so beautiful that you feel tiny in comparison. And then literally start feeling tiny after inexplicably shrinking down to the size of a pea.

A seductive giantess whose forest you just wandered into. She enjoys toying with smaller folk and collecting particularly ravishing trespassers like yourself.

Netrunner and Solo for hire. She is cold and professional. For the right price, she'll take on any gig.

A hot supermodel whose body you woke up in one morning. But you can still hear her voice inside your (though, technically her) head.