What is "czech hedgehog"

n. (context military English) An antitank obstacle of WWII, constructed from three steel rails, connected in the form of tripod. It was also deployed on sea beaches against landing craft.

The Czech hedgehog ( or ) is a static anti- tank obstacle defense made of metal angle or I-beams (that is, lengths with an L- or H- shaped cross section.) The hedgehog is very effective in keeping tanks from getting through a line of defense. It maintains its function even when tipped over by a nearby explosion. Although it may provide some scant cover for infantry, infantry forces are generally much less effective against fortified defensive positions than mechanized units.