Nemesis Comet's Defensive Alien Gas

A colorless, odorless vapor released from ruptured silver periscopes emerging from the Nemesis comet's crash site. The gas incapacitates unmasked organisms within seconds, targeting the nervous systems of human police officers monitoring the perimeter. Officers report sudden radio failure before collapsing, their reactions suggesting systemic physiological disruption rather than mere suffocation. The gas's rapid effect reveals the comet's active defense mechanisms, though its exact chemical composition remains unknown aside from its environmental aggression.