Right before the first "roller coaster" structure there's a big paper wasp nest in a tree to the right of the trail. It's at the intersection where you can go left to skip the structure or right to ride it and add a little more trail. I got stung twice - on the ear and on the lip. Very painful - they are mean and angry. I probably would have been OK just passing through but I stopped to retry the structure and that's when they got me. They'll probably be there until it cools down or until someone more reckless than I removes the nest.