What does Persephone do to Grover when alone?

Persephone doesn't do anything to Grover when alone.

It sounds like you might be thinking of a specific scene or moment from a book or movie. Could you give me more context?

For example:

* What book or movie are you referring to?

* What is the general situation?

* Why do you think Persephone might do something to Grover?

With more information, I can give you a more accurate answer!