Ed: All this week Massive is marking Halloween with stories of scary, witchy, and downright ghastly stories from nature. 

Larval Leucochloridium paradoxum, more commonly known as the green-banded broodsac, is a parasitic flatworm ingested by snails feeding on bird feces. As the parasite grows, it comes to take over the snail's tentacles, leading to one to two appendages resembling wriggling caterpillars or maggots  — known as mimicry. 

Mimicry is an umbrella term used to describe when organisms look like other things. For example, insects can look like twigs or leaves to blend in with their surroundings, anglerfish attract prey by wiggling their esca (an adapted spine) to resemble a smaller fish, and some flowers are shaped like female insects to attract males for pollination. L. paradoxum takes mimicry a step further by drawing the snail out into the open to increase its chances of getting gobbled up by a bird.

Researchers have also found snails infected by L. paradoxum tend to stay in open, better-lit places and on higher vegetation, making them an irresistible snack for birds. Once in the bird, the parasites continue their life cycle, turning into adults, reproducing, and laying eggs. These eggs are released through bird droppings, and the cycle continues!

But the green-banded broodsac is not the only parasite that uses sinister mind control or mimicry to make its way through life. Toxoplasma gondii causes behavioral changes in mice to make cats eat them, and Myrmeconema neotropicum infects worker ants, causing a berry-like blob that will attract birds. 

The worst mimicry of all? Raisin cookies that trick me into thinking they're chocolate chip.

Ed again: The views shared by the author in this article do not reflect the cookie-related positions of Massive. We support oatmeal raisin cookies.