Condensers Down

This is a radiant quest that will trigger when one of your settlements gets attacked by the Fog creatures. As long as the condensers are down, all sort of mutated animals will continue pouring in to the settlement, usually from one location. The sooner you can get the condensers back on, the faster the attack will stop. If your defenses are good enough and if your settlers are adequately equipped, you can just let the condensers get fixed automatically to maximize the experience and loot you can get from the slain creatures. Take note that these enemy waves may contain Legendaries and dreaded Fog Crawlers.