Internet users are astounded by an incredible before-and-after of a puppy who grew into a "werewolf".

Lupin, 5, lives in South Carolina with owner Alyssa, 37, and her husband. The dog has found himself an unlikely social-media star after his transformation from puppyhood was shared online.

Alyssa told Newsweek that Lupin is a mix of a German shepherd, Alaskan malamute, and "about 13 percent" Irish wolfhound. Giant breeds are mixed "far back" in his genetics, including the English mastiff, Anatolian shepherd and Great Pyrenees.

The rare mix of breeds is a highly unusual one to see out and about, and even on the internet, so a video shared to Alyssa's TikTok account, @lupin.the.direwolf, has had a huge response, racking up over 521,000 views in just six days.

It shows Lupin as a puppy, looking rather like a tall, black German shepherd. He is relaxing in the garden with a few feathery hairs on his chin, with the words: "The little hairs on his chin MIGHT grow out."

The screen then switches to Lupin now: a positively enormous, 150-pound, black dog with a long, gray goatee and feathers in his ears. He looks far more than 13 percent wolfhound, alongside the words: "5 years, 7 inches later."

Data and logistics worker Alyssa told Newsweek that Lupin is part of the Direwolf Project breeding program by Lois Schwarz. This aims to create a "loving, kind and intelligent Velcro dog in a healthier giant breed of dog".

Alyssa added that "the goatee was a complete surprise, honestly."

"When he was a baby, he only had a few gray whiskers on his chin that we thought may fall out eventually. Ironically, they multiplied and grew into the patchy featherings you see on him today," Lupin's owner said.

It's not just online where people are excited to see such an unusual breed, Alyssa added, as people are full of questions for her if they come across Lupin in person.

"It is fun to see people smile when they meet him; he gets excited and rubs his face all over their legs just like a giant cat," Alyssa said. "Our most-common comment is how he looks like a werewolf, which is quite true."

Lupin's breed, the American Alsatian, has not yet been recognized by the American Kennel Club (AKC), but aims to recreate the look and size of the dire wolf, a breed of giant canine that went extinct around 9,000 years ago.

The San Diego Natural History Museum says that the dire wolf was similar to modern-day wolves but with larger jaws and teeth, and far heavier; it weighed between 125 and 175 pounds, compared to the modern wolves' weight of between 66 and 145 pounds.

Alyssa said that she first came across the project in 2011, and visited the breeder and the dogs multiple times before finally seeing a photo of puppy Lupin in 2019. She instantly knew "that was our boy".

Lupin's extremely unusual look led to a huge reaction online, with one commenter jokingly comparing him to a legendary beast and writing: "You are about to go on a mythical journey."

"I feel like I should know some kind of password in order to cross the bridge now," another posted, with one agreeing: "He looks like a beautiful old wise wizard."

Alyssa said the video going viral was very unexpected as she only tinkers on TikTok, but it has been "joyful experience to see how many people's days can be just a little bit brighter because they stumbled upon us."

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