If you don’t like small spaces, this obstacle will be a challenge for you. Crawl through a series of pipes that force you downhill into some freezing mud, then a slippery uphill climb to the other side. Your legs will be useless in the narrow confines of the Boa, so use your arms to pull yourself through this obstacle. There really is light at the end of the tunnel. Check out photos and video of Boa Constrictor below.