Unidentified Danish coin 1889 with one very strange side.

Hi.
I can't identify this coin.
What I know:
It's Danish.
Christian IX
Diameter 16,5 mm
It seems to be larger than 10 öre and smaller than 25 öre.
One side looks very odd.

Any idea what kind of coin this is?

very curious!
the back seems prepared for engraving, either ground down from original design or struck on purpose, like an award medal, but that seems odd too, being so very small, such medals are generally crown sized, or at least half crown.

can you try for better pictures - more light, better focus.

Probably one of those coin like buttons, cufflinks or the sorts

Hi.
Sorry, right now I only have my mobile phone to take photos.

To me it seems like one side is 5 cent Danish West-Indies.
https://en.numista.com/catalogue/pieces17055.html
However, they don't exist for 1889.

Btw, on the back is a small star.

Bust looks quite different, typical for such buttons to be of lower quality. If you look at the star side, at the center it seems to look like a broken of shank from a button.