First developed by the British, what was the name of the World War II-era anti-submarine mortar that threw groups of projectiles ahead of the attacking ship?

First developed by the British, what was the name of the World War II-era anti-submarine mortar that threw groups of projectiles ahead of the attacking ship?

Gopher
Hedgehog
Porcupine
Groundhog
Possum

The correct answer is Hedgehog