Mud-covered creatures slide down hills, slither over ropes, and plunge headfirst into tangled cargo nets. Around them, the towering walls of an abandoned rock quarry reverberate with the crowd's animalistic growls and cheers. Underneath each coat of mud stands a runner participating in Caveman Crawl's 5K adventure race and mud-run course. Adult racers, separated into timed waves, race against their shoe-clipped timing chips as they bound over, under, and through more than 20 annually changing obstacles. Past challenges include plunging down a 500-foot water slide, leaping over lily pads, and tiptoeing through a quiet library. Smaller racers, aged 4–6 or 7–13, navigate a shorter course with compact versions of the larger obstacles. Along a newly added mountain-bike course, Dual Sport Challenge participants pedal across rocky hills and through swaths of mud and chilly water, all while giving the right of way to commuting mountain goats. The race ends with a massive barbecue where participants celebrate their victory over nature and often receive prizes while refueling with food, drinks, and live music.