What after action_unlikely_intent in case of UnexpecTEDIntentPolicy?

I am working to fine tune my rasa chatbot to predict actions suitably. I was going through config.yml topics. I came across UnexpecTEDIntentPolicy which outputs action_unlikely_intent in case a strange intent is detected. I also went through Youtube videos of Rasa, but nowhere did I arrive on what to do after action_unlikely_intent. What does the action do? What intent should I supply after the action? What does the action_unlikely_intent even do as a next task? What should the user expect as and to do for action_unlikely_intent? Do I need to change or tweak my stories to accomodate this special action? Should I even write a custom action for action_unlikely_intent?