"Gak! Cough! I just swallowed a bug."
Spiders of the moonlight, weaving webs of smoke, mist, and moonbeams.
Sometimes, someone is watching in the middle of the night.
Rats the size of cats, these insectivores are tree-top hunters. While they are useful to farmers and people, they are considered pests.
It is whispered at harvest bonfires that sometimes swarms will combine into a monstrously huge pile of Black Leaf Bugs, able to instantly stop anything it comes across. What is left explodes in a shower of maggots.
Real World: some Indians in the Amazon treat their eyes with a traditional potion applied with palm leaves. Brutally painful, the drug alters vision, giving the jungle's dense green walls greater texture and dimension. You could adapt this to desert or swamps, or other hard to navigate regions.