Alpha Warrior: "Alcatraz: Tree Tops" obstacle
I normally don't really consider myself to be afraid of heights, but this one scared the crap out of me. It doesn't look like much from down below, but from where I was standing, you're about 30 feet up, and though there was a safety net, it fades out of view and all you see is the ground beneath you (and Zaeley). Took me a few minutes to build up the courage (and/or fight off the common sense of sitting this one out), but I finally did it.