Ascaris lumbricoidoes, the intestinal nematode is the largest parasite in the human measuring up to 40cm long 1.
They may be asymptomatic or a large bolus of worm entangled can result in intestinal obstruction or perforation.
Some large worm migrates through biliary tract causing obstruction, biliary coli, cholecystitis, cholangitis or even intrahepatic abscess (rare)
Some large worm can even manage to migrate up to esophagus provoking coughing and oral expulsion of the worm.