The pickelhaube was the spiked helmet used by the Prussian army of the Nineteenth Century, as well as other militaries, including modern ceremonial troops of Chile. It became a recognized symbol of German military tradition during and after World War I, even though the Germans prudently replaced it during that war with more protective headgear.
This photo is one of several from a 2019 tradeshow attended by a German tactical gear blog called Spartnat. At that show, the German helmet producer Schuberth offered a modernized version of the pickelhaube, now featuring a handy rail system. This may have been a joke.
-via reddit