An emperor scorpion

You had decided to combine her with an emperor scorpion. You had the woman strapped naked onto a table. She was a little difficult at first, but after you cast a dizzy spell on her she was much easier to handle. You are expecting her to grow a tail, so for safety precautions you had her facing down. The ritual could begin.

You collected two scorpion claws and a tail, then placed them on the woman's back. You placed your hand over it and summoned your magic. This put an ethereal glow over your subject. The woman started to become worried and asked "What are you doing?"

You chose to ignore her and continue the spell.

"Stop it." She said softly.

You continued to ignore her and persisted the spell.

The woman began breathing heavily. She felt something was happening to her.

"Stop it! Stop it, please! Somebody, help me!" She tried to say. She was too dizzy to resist at all and was completely at your mercy.

Finally the preparations were complete. The merging could begin.

The woman's back became like liquid, allowing the tail and claws to disappear into it. While they were absorbed by the woman's body, she started to change.

First she started to grow a tail. It kept growing longer and arched upward like any regular scorpions tail. Black segments grew on her tail, including a stinger at the end.

Her hands and feet also grew black bony segments covering them.

There were no further changes. You were a little disappointed, you had expected more. But no matter, she would be a great specimen to study on.

Once that was done, the merging was complete. You ended the spell and retracted your hand.

You had turned the woman into a scorpion-girl.