Parasitic worms are well-known for causing deadly diseases and infections, especially in animals. What’s not common knowledge, however, is how clever they are in manipulating their hosts to do their bidding.

One particular type of parasite, called the green-banded broodsac, is a flatworm that relies on snails for its life cycle. Unlike other parasites, however, this worm doesn’t actually feed off its host. Instead, it turns the snail into a “zombie” of sorts, controlling it in order to be at the right place and the right time… so it can be eaten by birds.

Why in the world would a parasite want its host to commit suicide, you ask? The answer isn’t as counterproductive as you think.

This snail looks kind of funny, doesn’t it? That’s because it’s been infected with a parasitic worm, called the green-banded broodsac, which takes up residence inside its tentacles. The parasite now has complete control of the snail’s brain—and it’s instructing the doomed gastropod, nicknamed a “zombie snail,” to climb to the tops of plant stalks in broad daylight.

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Now engorged, the snail’s tentacles seem to pulsate as the parasite inside moves. It’s not a coincidence that the tentacles look a lot like maggots…

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Maggots, by the way, happen to be a favorite treat of birds. Fooled by the parasite’s disguise, birds eagerly devour the zombie snail.

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Now that the parasites have infected a new host—the bird—they thrive inside their guts, releasing even more parasitic larvae.

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The bird excretes the larvae in its waste…

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…Which is happily gobbled up by unsuspecting snails on the ground below. And thus, a new cycle begins!

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Watch the entire process below. It’s really quite ingenious on the parasite’s part…

How creepy is that parasite? It’s unfortunate that the snails don’t get much out of this deal, but alas, such is the circle of life! At least they get a cool makeover before their untimely demise.

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