The video, posted on YouTube, invited viewers to take a look inside the inspirational life of a puppy who may look a little different, but really isn't that different after all.
Duncan was born with severely deformed rear legs and pelvis. The bones in his legs were completely fused by the time he was eight weeks old and there was no way to correct them.
Amanda Giese of Panda Paws Rescue took him in.
Amputating his rear legs was the way to give Duncan the greatest chance at a good life. The surgery was done when he was 12 weeks old. Now, at 9 months old, Duncan can do what any other pup can do - even climbing up and down stairs.
He has no idea that he doesn't have two back legs - and we don't plan to tell him, Amanda says in the video.
They fitted Duncan with a wheelchair but he wouldn't use it.
Everything that he does he's had to learn the hard way, says Amanda.
At the end of the day he's an all-around average puppy.