The Sludge has survived a previous attempt to destroy it, and is back regenerated after being struck by lightning. As it wreaks havoc in Canada, Hanley and Slade discover it is now immune to the formic acid they had previously used to destroy it. The Sludge heads for a naval base, sensing the presence of an atomic sub - upon which it can feed. The sub lures the entity out to sea, where it is found to be vulnerable to the stings of Jellyfish.; Embittered scientist Stasky goes on the rampage with his Z-Ray.; Revelle tries to use The Spider as a distraction to keep the police busy while he robs a bank, but The Spider figures out his plan and brings him to justice.; Nolan chases down two would-be assassins.