The substance of one's nose slurped out of one's fingernails, ideally a big ole booger jellied in white mucus (the oyster) slurped from the tips of one's French-manicured fingernails (the oyster's shell)
A trip to a grocery store, convenience store, or gas station for the sole purpose of buying an excessive amount of junk food and sugary drinks, usually with friends. A chud run often happens late at night and ends with everyone involved hating themselves afterwards.