When it comes to designing creepy creatures that lurk outdoors, horror writers could take a page from the plant world.

Imagine roaming a dimly lit forest and finding a stalk covered in eyeballs growing out of the ground, or a foul-smelling “octopus” that looks like it’s reaching for you with slime-covered tentacles.

Some of the most nightmarish creatures on Earth are plants and fungi that can’t chase you but manage to look malevolent anyway. Sometimes there’s logic behind our fears, says fungi researcher Kathie Hodge at Cornell University. Some mushrooms and plants are very toxic, so being repulsed “comes from our deep need to avoid things that will hurt us,” Hodge says.

Others are harmless to humans and simply evolved to look