Seriously, who can resist a pic of a cute dog in a headband? Or a cute dog getting muddy? Or a cute dog conquering a mini version of Everest or Berlin Walls? (Ruff Mudder Philly, we're looking at you.) For no reason other than your viewing pleasure, we submit the following dogs, all stars of Tough Mudder's Instagram, who are Probably the Toughest Pooches On the Planet. You're welcome.