You enjoy a rare steak
“Ingesting raw or under-cooked beef or pork can lead to [infection by] the taenia species of intestinal tapeworms,” says Dana Hawkinson of the University of Kansas Health System. “Eating certain raw fish can lead to [infection by] the Diphyllobothrium species of intestinal tapeworm.
Additionally, ingestion of contaminated food or water can lead to an ascaris infection.” Ascaris intestinal roundworms can grow up to 35 centimeters and lead to intestinal blockage, so you definitely want to avoid them.