Vanishing Woods

"Y'know, my Grandmother once told me that if you see a part of the woods is different than it was the day before, to turn back and head home for the day" Aulir said calmly climbing over a fallen branch.
"Seriously? You say this NOW?" Leera says gesturing to their surroundings.

— Two unfortunate souls who wandered too far into the Vanishing Woods off the main path

These woods are unmappable by anyone who doesn't have fae ancestry and even then, mapping it would be hard. They only show up once a year and there is a festival held in the village that comes into this realm with the woods. The village is only accessible when the festival is set up and ready to go. The rumor is that the part of the faewylds that comes through to this plane are different parts of the faewyld every year. There are a few fae pests that have decided to infiltrate local granaries and food stock piles, such as imps and gremlins. However, they are completely easy to get rid of, just offer them a trinket of moderate value and they'll be on their way. Letting them stay can also be beneficial as they deter thieves. If you let them stay and give them trinkets, they will protect your crop for the price of the souls of the thieves. No one suspects a grain faerie to steal your soul.

The Village in the Woods

The Wandering Village is a place many of the surrounding communities avoid going to every year. There is a festival held in it when the Woods appear. There are, however, unsuspecting children that attend the festival, having snuck out of their homes to do so. The festival seemed to change the children. Many of the parents don't notice the fact that their child seems to change in behaviour.
The truth.

These are not their children anymore. They are changelings. Their children are gone. Most likely eaten by Fae.

Vanishing Woods by Leashea via Midjourney