Someone prone to mood swings or changeable behavior could be accused of being “capricious,” or “given to sudden and unaccountable changes of mood or behavior.” The word might look familiar as related to the 10th sign of the zodiac, Capricorn, which is often represented as a goat. In Greek myth, Pan (the goat) was attempting to escape Typhoon and jumped in the water mid-shift into animal form. The half that was above water assumed goat form, and the bottom half formed into a fish tail — how capricious.