The Bunker Cluster (バンカークラスター Bankā Kurasutā?) is a cluster munition warhead developed independently by England that releases hundreds of explosive shells that are made to pierce into underground weapons. So fearsome is the weapon that under the influence of the Roman Catholic Church, the European Union forced England to sign a treaty to ban the weapon. The weapon is later used under Carissa's coup, the British Halloween, for the first time since the ban, most famously in the Battle of Buckingham Palace.