Imperial Germany’s 1888g 20-pfennig, struck in Karlsruhe of copper-nickel. This coin is a second-year example of the new, larger 20-pfennig piece introduced in 1887. (The silver 20-pfennig piece—a tiny coin, somewhat difficult to use—had not been coined in a decade. But that wasn’t in itself unusual; many German minor coins saw significant pauses in production during this period.)
The year 1888 was, as is widely known here on the Forum, the “Year of the three Kaisers,” so absent better information, I suppose this particular coin could be an issue of Wilhelm I, his son Friedrich III, or his grandson Wilhelm II.
Germany’s copper-nickel 20-pfennig pieces are relatively tough to acquire for a German minor coin, and one reason why was their early retirement from circulation on January 1, 1903.
Of particular interest, I think, is the prominent wreath surrounding the eagle. It’s only my own guess, but I strongly suspect that German coin designers—who by this time had seen the confusion between the similarly-sized silver 50-pfennig and copper-nickel 10-pfennig—were doing something special in an attempt to avoid confusion between this new copper-nickel 20-pfennig, and the silver 1-mark.