Three pairs of legs on thorax-segements, two big stigmata on each segement on the abdomen, about 8cm long. Four pairs of pseudopods on abd.segements 3,4,5,6 and the last (9th or 10th). Spits brown, odorless liquid when pushed with a stick and bites stick mith it's big black mandibles.
Found crawling on a bikeway between two wild meadows. Between Rhine, houses and woody hills (s. red circle on 3rd picture).
When I first saw it, I thought it to be a larva of the stag beetle Lucanus cervus, of which I know that it lives in that area. But their larvae ar whitish and, except the bright brown head, not coloured at all. Though the size seemes to fit, since Lucanus larvae can reach 11cm in length.