If you’re looking for a creepy science lesson, check out parasitism in nature.
There’s a type of fungus that takes over an ant and causes the ant to crawl up a branch and latch on, where the fungus grows and spreads. Different types of fungus can attack different animals.
National Geographic has a short video about this.
BBC has another video about this.
Deep Look has a good video about a fungus that attacks a fruit fly.
But ants don’t always get a raw deal from fungus. Some types of ants farm fungus for food (Deep Look again):
There’s also a parasitic worm that takes over a snail and causes the snail to turn into a colorful and easy-to-grab treat for birds. Then the worm reproduces inside the bird. See Wikipedia or Wired for articles, or see National Geographic for a video.
National Geographic also has a video about a type of wasp that invades a caterpillar.
MoMooMath offers various examples of parasitism.
StoneAgeMan has a video about mutualism, commensalism, and parasitism.
Image: Gilles San Martin