A hedgehog slice is an uncooked flat, square or bar-shaped chocolate snack/dessert, similar to Rocky road but with alternating lighter and darker areas.

In some languages it is named after its appearance, such as Swedish radiokaka (named for both its resemblance to old-time radios and its ability to be eaten soundlessly so as to not disturb radio broadcasts), Turkish Mozaik Pastası or Greek Mosaico.

Many German histories refer to a 1920s recipe from baking firm Bahlsen that combined chocolate with packaged cookies.

[4][5] The name "Kalter Hund" has been theorized to have passed into German through the Slovakian word hyntow (box-shaped trolley), which might have been a reference to the rectangular pans in which the dessert is often made.

[4] In 2017, inhabitants of Ronneburg made a 994.9 meter long cake, the longest to date in Germany.