Known only as Toco, the man spent two million Yen – which equates to £12,480 – on a lifelike costume to fulfil his fantasy of living on all fours.
Toco became an internet sensation and amassed over 52,000 subscribers on YouTube after he shared videos of himself being taken out for walks and attempting to perform tricks in exchange for fake dog food.
However, after finding it difficult to move like a dog, the YouTuber has had a change of heart.
“Dogs and humans have different bone structures and the way they bend their legs and arms, so it’s very difficult to make movements that look like this,” he said.
“Also, when they get dirty, they get dirt on their fur, so it takes a lot of effort to clean it every time.”
Speaking to local Japanese news outlet WanQol, Toco says he’s exploring his options.
He added: “I might realistically be able to become another dog, a panda, or a bear.
“A fox or a cat would also be nice, but they are too small for humans to try.
“I’d like to fulfil my dream of becoming another animal someday.”
Toco received backlash online after his first transformation, with many social media users mocking him for spending thousands on a costume that took 40 days to make.
But in a series of surreal videos posted to his YouTube channel, titled “I want to be an animal”, Toco shared his experience of being led on a leash and meeting other canines.
Footage showed him sniffing dogs in a park before rolling around on the floor.
Toco said his family members were initially “surprised” by his bizarre hobby, but they have come to accept it.
The original sheltie outfit was purchased from a Japanese firm called Zeppet, which creates costumes for films.
Toco now works with them to create his own outfits.
He added: “When I fulfilled that dream, this is how it turned out.
“I’ve wanted to be an animal ever since I can remember.”
It comes after Toco faced a crushing setback when he was cruelly shunned by real-life canines.
And the pooch-wannabe went on a mission to find his Lassie.