Panzer - The men of the panzerwaffe faced many dangers during their service life and one of the risks of their trade was not related to the actual figthing, but to the very uniforms they wore.
When serving in the panzerwaffe you wore black and the origins of that are somewhat unclear to me, but the two most common explanations are that black was chosen because the inside of the panzers were often filled with oil and smoke which would have soiled uniforms in the standard feldgrau (a greenish grey) of the German Army.
Another explanation is that black uniforms formed a connection with the proud traditions of the German cavallery - most notably the Totenkopfhusaren (Death's head hussars) who wore black uniforms when they fought for Prussia against Napoleon in the early part of the 19'th century.
The ancestry with the hussars also explains the addition of two death's heads to the collar patches of the panzer uniform (the Totenkopshusaren wore a death's head on their headgear), as can be seen in a closeup of our panzer gefreiter (lance-corporal)
This combination of practicality and tradition could unfortunately prove fatal to members of the panzerwaffe if they were captured.
With the black colour and the death's head their uniforms were very close in appearence to the dreaded uniforms most allied soldiers had seen in pre-war newsreels from Nazi-Germany: The uniforms of the SS who also used the death's head in their regalia.
Since soldiers of the SS had massacred US and British prisoners on several occations during WWII, some allied soldiers would welcome the capture of an SS man as a chance for some payback.
In fact the black SS uniforms were discontinued when WWII started, so if a German soldier wearing black with death's head insignia was captured and shot by Allied troops, he was most likely a member of the panzerwaffe.
A US veterans account written many years after the war show how common this misconception was.