A slow spreading, but dangerous STD, originally extracted from the monstrosity known as "the ugly". There is no known cure against the ugly at the moment. Early stages are undetectable, but later stages include symptoms such as rapidly growing bush, balls on your chin, and penis falling off.
A sunburn or suntan focused on the left arm. It is caused by the left side of the body being the only half that gets exposed to sunlight while driving. Presumably, it would be located on the right side of the body in countries where they drive on the left side of the road.