Also known as an Anti-Submarine Projector, the hedgehog is an ahead-throwing anti-submarine weapon developed by the Royal Navy of the United Kingdom during World War II. The weapon fired a number of small spigot mortar bombs from spiked fittings. The bombs exploded on contact, rather than using a time or depth fuze as depth charges did. They achieved a higher sinking rate against submarines than depth charges did. The device was named for the way the rows of empty spigots resembled the spines of a hedgehog.