Sd.Kfz. 8 with 8.8 FlaK 18 "Bunkerbrecher"
Panzerjäger Sd.Kfz. 8 mit 8.8cm FlaK 18

One of the first real for tank hunting created vehicles of the Wehrmacht. The first saw action during the invasion of Poland 1939! It was created to give anti tank support to the "Leichte Divisionen" (mechanized infantry divisions) that should keep up with the fast tank divisions. The units belongs to the artillery amour and was grouped in anti tank "Abteilungen" units.
It's nickname "Bunkerbrecher" means bunkerbuster and comes from its second infantry support role with breaking bunkers and trenches with the capability for direct fire of a strong 8.8 cm, time or impact infused, round with a very high velocity and accuracy. But, it's first role was smashing enemy tanks. Uncomfortable for that role, it was in Poland quite to overpowered and there was not a really need for that capability. So the production of that expensive vehicle was cancelnd after a few. At this time the Wehrmacht was planing to adept the coming new 5cm PaK gun as new anti tank gun and the StuGs (assault guns) for the role of direct fire support for the infantry.
Uncomfortable its was until middle 1940 as the new 5 cm Pak 39 was ready developmented, and not build yet. So in France the need for such a mobile strong anti tank gun was back because of the well armored french tanks. But no more "Bunkerbrecher" was build. So this need leads to the developing of the new Marder I series. Strong guns (mostly 7.5 cm Pak 40s) with a little protection for the operators on very much cheaper chassis as ewen the expensive (and needed) half-tracks.