A DOG owner who was told she was buying a gray Labrador retriever puppy has been left stunned after it grew even bigger than her.

The speechless pet lover had a clear message for the seller months after she took home what she thought would be a mid-sized pup.

NINTCHDBPICT001098135680A dog owner has learned the truth about her adorable puppy after he exploded in size Credit: TikTok/crawftz NINTCHDBPICT001098135679Aliyah thought little Nico was a Labrador retriever, but was stunned to find out he’s a Cane Corso Credit: TikTok/crawftz

Aliyah ( @crawftz ) posted a now-viral video showing off the she’s seen in the past year and a half.

She shared a clip of the wide-eyed puppy with the caption “To the person who sold me a grey lab puppy” before flashing to the now-massive dog and writing “wtf.”

Aliyah learned her puppy, named Nico, was actually a Cane Corso, which is a hulking Italian breed of mastiff used to protect livestock.

TikTok users were stunned by the transformation, and many joked that they needed Nico’s fitness routine.

“Who’s horse is that,” commented one stunned user while another said, “How do his muscles have muscles.”

“Met him at gym once, nice guy,” teased a different user.

Despite being an intimidating guard dog, the Cane Corso is known for being an even tempered gentle giant that’s easy to train.

Nico appears to fit the stereotype as Aliyah is constantly posting adorable pictures of him cuddling up to her like a lap dog.

The American Kennel Club describes the Cane Corso as “smart, trainable, and of noble bearing,” adding it’s a “peerless protector.”

They have an average 28 inch shoulder span and often weighs more than 100 pounds, making them look like “intimidating creatures.”

“Corsi are intelligent, loyal, eager to please, versatile, and intensely loyal to their humans, but are also assertive and willful, and can end up owning an unwitting owner,” said the club.

“As with any other big guardian dog, responsible breeding and early socialization with people and other dogs is vital.”

Aliyah isn’t the only dog owner who was shocked to learn the truth about her pup.

One owner before realizing it wasn’t even a dog.