I don't have much Elves, but I do have the Little Mermaid set. I'm not sure if it counts for Autumn Animals, but I decided to create a grotto for Flounder to hibernate in for the winter using what I had.
I'm very new to creating MOCs but I loved the idea of this challenge. I wanted to make an underwater cave that had part of the rock sticking up above the water's surface. Again, not sure if it works for the contest, but I wanted to participate just for fun.