Biological Nightmares of the Animal Kingdom

The vast majority of animals on Earth are actually biological nightmares living right under your

nose. It starts with flatworms, creatures so simple they eat and poop out of the same

hole because they don't have a real body cavity. If you cut one in half,

it just grows two new heads. Then evolution got weirder with roundworms and rotifers that

have a fake body cavity. Some, like the horsehair worm,

literally mind-control insects to drown themselves. Finally, arthropods showed

up with armor and jointed legs to dominate the planet. We are just guests in their world of

exoskeletons and parasites.