This unusual item is a coin bank which has a 3-D effect baseball stadium and baseball that seems to float in the air.    Coins put in the slot on top "disappear" -- that is, they look like they are going into the cube containing the stadium and should appear in the stadium with the baseball but instead they are not visible.   The trick is that there is a separate angled part "behind" the 3-D stadium.    It holds several dozen coins which can then be retrieved by removing the top (coin slot) face of the slightly less than 3" cube.  

This comes from Japan and represents the Seibu Lions but it is the "magic" of the disappearing coins that is the great attraction for young kids.    Unless you know how it works, where the coins go seems to be a complete mystery -- someone not knowing how it works will struggle to figure it out (especially since finding the way to open the correct face of the cube is not at all obvious.).   

I have one of these which I am keeping that my sons enjoyed 20 and 30 years ago while our six grandchildren have delighted as well these past 10 years.   It really is a great item and I think pretty much one of a kind -- that's why I'm keeping one for us while I sell the advertised one, which has simply been in storage for the past several decades.   (I think it is from the 1980s.)   

(I originally had three of these that a friend in Japan sent me and I don't know anyone who has one of these other than myself and one person to whom I sold the only other one I had -- that person was delighted, as my feedback will show and I'd hope anyone buying this last one I am selling will be as pleased with it as my kids, grandchildren and I have been over the past 30 years.)

I've never counted the number of coins that the bank can hold but it is several dozen anyway.   We've always used pennies, just for fun, but it could probably serve as a more traditional piggy bank as well.