The Incident of the Giant Ammonia-Breathing Space Crabs

All human life is under threat with the arrival of the Giant Ammonia-Breathing Space Crabs! Our weapons seem to be useless against these hyper-sized crustaceans. Can mankind be saved? There may be a chance, if Dr. Walter Niemann's hunch is correct - and the Alien Invasion Response Bureau Action Group (AIRBAG) can make the wily scientist's plan work!