This is Duncan Lou, a 16-week-old boxer puppy who was born with severely deformed rear legs and pelvis. According to his YouTube page, the bones in his legs were completely fused by the time he was eight weeks and there was no way to fix the situation.

We chose to amputate his rear legs making him a double amputee & giving him the greatest chance at a wonderful life when he was just 12 weeks old. Duncan Lou Who doesn't let his unique differences slow him down & he doesn't know he is any different. He is now 16 weeks old, does physical therapy every day to correct the damage to his spine since birth, is regularly going to be doing hydrotherapy for life to help support his muscles and he also has a custom wheelchair to give him a second option of mobility. Duncan Lou Who is on a mission... to inspire YOU!

Dude, consider me INSPIRED. I'm about to go out there and run a marathon even though I've never even walked a 5K. That's called INSPIRATION/the kind of thing that leads you to shitting yourself on mile 6 before collapsing into a pile of your own sweat and vomit and then begging nearby runners to cut off your legs and throw them in the bushes so they'll never betray you again. #inspired.