- I'm scared.
- I heard something.
- I'm not tired.
- I can't go to sleep.
- I don't know how to go to sleep.
- I want to see what you're doing.
I told him to go back to sleep and that if he wakes up as a shark-boy, I'll find a big container that he can go to school in.
This seemed to appease him and he went back to bed. And I haven't heard a splash out of him since (about 10 minutes).