I’m sure you’d like to pretend that you have nothing in common with a tapeworm.

A tapeworm starts off as an egg which then develops into a cyst. Inside the cyst is a ball-shaped creature with hooks that it can use to crawl around its host before growing into an adult. Many species are made up of dozens or hundreds of segments called proglottids. Each proglottid may be equipped with both eggs and sperm-making organs. As an adult, a tapeworm also grows a head-like end often equipped with suckers or hooks of its own. This strange organ is called the scolex. (The shark tapeworm in this photo is displaying its fearsome scolex.) While the tapeworm lives in the gut of its