In 2368, an asteroid from the Pelloris field threatened Tessen III and was destroyed by the USS Enterprise-D. However, a metal parasite from the destroyed asteroid infested the Enterprise and severely distorted the ship's systems, including life support. The Enterprise then returned to the field and lured the parasite back to the field with a particle beam containing nitrium directed on the field. (TNG: "Cost of Living" ) According to the script, the pronunciation for Pelloris was pel-ORE-us. [1]