Pyramid Shaped Key

The Pyramid shaped key is a key the shape of a pyramid openning the secret room in the sewers of Citadel Island, where Sendell's Ball is surrounded by a cage of ice.

The key was kept by Mies van der Rooh's father, the old rabbibunny who lives next to Twinsen on Bug Street. After Twinsen gives his neighbour a Gallic Acid, he is able to use it to restore a map of the sewers. This map turns out to mention the key, which the rabbibunny gives to Twinsen.

Twinsen uses this key with the keyhole on the floor in Green Corulla Street, which makes the door to the secret room open.