Hedgehog

A small mammal, of the family Erinaceidae or subfamily Erinaceinae (spiny hedgehog, the latter characterized by their spiny back and often by the habit of rolling up into a ball when attacked.)

Any of several spiny mammals, such as the porcupine, that are similar to the hedgehog.

A type of moveable military barricade made from crossed logs or steel bars, laced with barbed wire, used to damage or impede tanks and vehicles; Czech hedgehog.

A spigot mortar-type of depth charge weapon from World War II that simultaneously fires a number of explosives into the water to create a pattern of underwater explosions intended to attack submerged submarines.

To make use of a hedgehog barricade as a defensive maneuver.

To array with spiky projections like the quills of a hedgehog.

To curl up into a defensive ball.