Bonefrog, Charlemont

Frogs aren’t exactly known for being fierce, but The Bone Frog Challenge’s namesake skeleton frog makes more sense when you know that it is the unofficial mascot of the Navy SEALs—the creators of the rigorous race. The mascot honors the SEALs’ predecessors: the Underwater Demolition Teams of World War II, who were dubbed “Frogmen” for their ability to work underwater.

The Bone Frog Challenge challenges everyday civilians to act like SEALs, with an emphasis on functional fitness. While the muddy, timed races measure up to 12 miles long, they require more than speed and endurance. The military-style obstacles force participants to draw on reservoirs of strength, agility, and creativity to scale walls, swing on ropes across trenches, and slither under netting through puddles of mud. Although the races champion hard work, they also focus on fun, welcoming competitors across the finish line with music-filled after-parties complete with spreads of food and beer.