She goes to sleep

It took Emily a small bit of time to calm down, but she eventually did. As she left her bathroom, she began to think.

'OK, I'm a Dark Elf now. That's quite a problem.' Emily thought. 'I can't exactly go out in public like this. Dark Elves don't exist in this world. They're just fantasy. I'll need a disguise. Ugh, that won't work with my friends. I'll have to explain this to them. Hope they understand... or even believe me.'

As she thought to herself, she tugged at her panties. Just like her pants, they felt rather tight on her.

'Geez, I'll need to find underwear that fits someone as tall as I am now.' Emily thought.

Unknown to her, though, it wasn't just her height causing this tightness. Her lower body had expanded somewhat. Her hips and thighs had bloated a fair bit, and her previously toned rear was replaced with a bubble butt.

Emily didn't notice this, though, as she went over to her bed. Whatever happened to her, she was incredibly tired, and just wanted to sleep. Collapsing on her bed, Emily instantly passed out, going right into dreamland.

-------

Emily's dream was rather... bizarre. She was extremely high in the air. She saw multiple other types of fantasy creatures, a strange land, and the book she had found that caused her change.

One really strange thing she saw in her dream was that she was sitting on a gargantuan pair of obsidian black orbs. Emily had assumed they were some odd mountains, but they were too soft for that. She eventually realized what they were: her butt cheeks, bloated to immense sizes... and still growing. The last thing she saw in her dream was the expanse of her ass reaching a coastline.

--------

Emily woke with a start. She quickly looked down at herself. She was, indeed, still a Dark Elf. For some reason, she could remember her dream clearly. Remembering, she got out of bed and looked at her rear. Sure enough...