A large vertical cave has a constant, strong wind blowing out of it from the bowels of the earth. If one was to jump into the currents they would have a controlled ascent on the winds till they reached a height where their weight and the winds force reached equilibrium. Impossible to climb down naturally. What is it? Natural winds from the earth or a complex magical protection for an underground lair?
Mining in a certain area turns all exposed skin (maybe just parts that are actively disturbing the chemicals that cause the reaction) of the those doing the mining to a dark blue color. Will wear off taking as many years/days spent in the mine.
Sneezing Sickness - A strange plant infection that causes its victim to spread the plants seeds by sneezing them about. Larger lumps of phlegm or saliva sprout is spat out in a sunny place, producing more of the plants. As the Magical version of seasonaly allergies the affliction is limited in term and non-life threatening.