I've always wondered this, but are there actually any confirmed kills by pickelhaube, or is the spike merely for decoration?
This, pretty much. The spike isnt even sharp, so not really viable.The spike is a decorative feature (and originally, very early in its history, a defensive one). The force needed to drive it into an enemy's body is so great it makes a lousy weapon.
The spike was indeed purely decorative, and if I'm not mistaken for parades it was removed and a plume was placed in it's base. (so the spike itself didn't hold the plume)AFAIK the spike was purely decorative, originally used to hold a plume for a parade dress. I never heard about someone killing anybody with it, but it should be theoretically possible, especially if the spike hit the throat. I can imagine that in a melee a soldier after looosing his rifle uses the spike of his helmet as a last chance weapon, but only in very close, hands-on-each-other-throat kind of combat. And certainly not with the helmet on his head.
But a vision of German infantry charging with their heads down and spikes forward like bull-style is quite entertaining.