Does anyone know what this is?

A radish flower maker ?

It is a fresh pineapple corer.

Looks like a pineapple slicer. You cut off the top of the pineapple and then push this down in a back and forth motion then pull it out when you get to the bottom. The core will be in the middle and your pineapple will be in slices.

i would agree about the pineapple corer except for the taper on the "handle".

As you cut deeper into the pineapple as you twist/saw your way down you will chew up the top pf the fruit.

It would work if you cut slices of pineapple first, then used the utensil on each slice

Donut maker

I have one. It was my father in laws. It’s a donut 🍩 cutter. We made donuts together with it.