Senior Airman Danielle Sturdivant crawls through the "electric eel" obstacle during the Tough Mudder. Senior Airman Danielle Sturdivant, with the 56th Communications Squadron at Luke Air Force Base, Ariz., crawls through the "electric eel" obstacle during the Tough Mudder at the Mesa Proving Grounds in Mesa, Ariz., on Jan. 14, 2012. SHARE: Download: Full Size (0.07 MB) Credit: VIRIN: 261643-N-ULW00-093.jpg Photo Gallery