Following the Spanish-American War, the Spanish tried to sell Rio de Oro to Austria-Hungary. The Hungarians nixed the idea, even though the Austrians were for it.
What if the Germans had purchased the place, either along with the rump Spanish East Indies or a bit afterwards?
If Germany already has a West African colony and naval base, might this butterfly away the German desire for Morocco (and thus the Agadir Crisis)? Or perhaps the territorial exchanges that occurred during the Agadir Crisis would be a bit different, with German Rio de Oro (or whatever it is renamed here) gaining some territory.
How do the British feel about a German naval base in West Africa? Likely not too happy.