Excalibur was a supernatural weapon held by the mythical King Arthur. He was the guardian of Britannia in the 5th and 6th millennia, that according to ancient English tradition. This particular seaworm's full suited armor is somehow compared to Excalibur, being known to live for about 400 million years from today. The tale of that charmed sword continues on today, in the form of an ancient insect that can be crushed within two fingers.