Build Me A Tapeworm

tapeworms are as strange as animals can get... These flat, ribbon-like creatures live inside the digestive tracts of vertebrates. The tapeworms that live in humans can get up to sixty feet long. They feed on our food, despite the fact that they have neither a mouth nor a digestive tract. Their bodies are like a kind of inside-out intestine, rippling with finger-like projections that absorb nutrients. Once inside us, tapeworms can live for decades, deftly escaping the notice of the immune system despite their being as long as an anaconda. Some tapeworms have hooks or suckers on their front end ("head" is too generous a term), which they use to anchor themselves in place. They can also swim upstream to meet food coming out of the stomach and drift back down the intestines to feed, releasing chemicals to slow down their host's peristalsis so that they don't get swept away.