What looks here like a snow-capped little tree full with icicles, is a “branch” of the coral tooth fungus. The fruiting body is composed of many branches and also reminds of a white coral. The specific epithet “coralloides” (= coral-like) and the aptly name “coral tooth fungus” obviously originate from this look. The german name is “Eiskoralle” (like “ice coral”).
I have not found this mushroom in the forest, where it likes to grow on beeches (but only very rarely, since the mushroom needs old or dead trees to live), but in the Kleinmarkthalle Frankfurt. Like many other mushrooms too, the coral tooth fungus is best fried and subtle seasoned with salt and pepper.