An unexpected release of gas out of the ear. Usually very obnoxious and mistaken for a fart. Clarks tend to occur after earthquakes or before going on a roller coaster and they release a toxic looking gas called AH otherwise known as EUWL!!
"I don't wanna go to the boardwalk man - all those roller coasters equal loads of clarks"
"I understand man, you don't want EUWL all over your girlfriend"