This is one of the rarest reversible plushies which is Tanemon and Palmon made by Play by Play and it does come up for sale quite a lot on eBay UK. The reversible plushie is about 15cm in size. Looking to buy one? Check eBay UK where they usually show up on. Last seen Summer 2019 on eBay UK.
Any questions just leave a comment down below.
Edit: Fixed the names.