Yossarian is a mystery to all sentient life. He is neither physical, nor ethereal. He isn't light, and he isn't dark. He's not chocolate, but not quite vanilla either.
Yossarian ("Yoss" for short) is the reason Conan O'Brien can't comb his hair right. By just his mere presence, he inflicts his will upon people.
Yoss is the reason that toilets flush the other way around in the southern hemisphere.
Yoss invented the cork. He also popularized Leg-Warmers, and then purposely un-popularized them.
His legend precedes him, in the way that lightning precedes thunder.