Thank you for the close read.

He could be the ornament, and if so, then she could be the shark. It's a possible reading. I did choose not to use the word "ornament" twice, because I did not want to limit the ending to that interpretation. The main point of the comparison for me is that the ornamental moon does not provide any substantive light, and his arm, if he is the shark, is therefore harmless, at least on that night.

I might come back to this poem later, so I appreciate the feedback!