The Slime People
The principal key is not spelled out in this defense of Los Angeles against scaly prehistoric humanoids from the sewers, who emit low sucking sounds and carry spears and kill and destroy and erect a wall of impermeable fog and a dome, too, while the city is evacuated and they lower the temperature to permanent dew point.
Their scaly hide is “self-sealing”, it is observed that when they fight amongst themselves, the spear-tip is removed and the shaft is hollow, thus impaled they die from wounds that do not seal.
Or, as the Roman spieler has it in Mel Brooks’ History of the World: Part I, hawking the latest invention, plumbing, “pipe the shit right out of your house!”
The rest is salt in the wounds.