Happy Days S06 E08 Fearless Malph

"Those were the days of the 1950's...filled with innocence and the promise of even better days to come."

Richie is writing a story about fears and phobias, and he finds out that Ralph is afraid of nearly everything. While Richie, Potsie, and Ralph are visiting a professor whose specialty is fear, lab mice become agitated. The professor concludes that it is a sign that a tornado is coming.