Lamina Mystery Engine

http://www.youtube.com/watch?v=BdDQCdfGfYY

You can also buy plans for this on ebay.

http://item.express.ebay.com/Lamina-Mystery-Engine-Plans-no-Stirling-no-Steam-Unique_W0QQitemZ160134018382QQihZ006QQtrZexpQQcmdZExpressItem

Stirling engine? Hidden battery?

It’s powered by the heat of that spirit burner there (the brass cylinder). It’s a Stirling engine.