At 6ft 5ins (1.96m) on his hind legs, Samson must be the perfect guard dog.
But to his owners, Julie and Ray Woods, of Boston, Lincolnshire, the three-year-old Great Dane-Newfoundland cross is simply a much-loved pet.
Samson - who weighs in at 19st 10lb (125kg) - is being billed as "Britain's biggest dog" after scrap merchant staff who weighed him contacted the media.
But the placid dog has been unsettled by the attention and has missed his quiet life, Mrs Woods said.
The couple adopted their pet from the local RSPCA centre when he was six months old and weighed a mere 16st 2lb (102kg).
Mrs Woods, 54, had only kept small dogs before while her husband, Ray, had kept larger dogs, including Alsatians.
"I said to my husband that, if he wanted a bigger dog this time then he could go for it," she said.
"When we called the RSPCA they said Samson was available, and if we arrived that day we could have first option."
When they arrived at the kennels, Mrs Woods said Samson "bounded over and pinned us both to the wall".
"But he really is a gentle giant and he has the kind of nature that means you can't help but love him," she added.
'Larger and larger'
Samson is still growing and, after going through several dog collars, he now has to have them specially made.
But the vet says Samson is not overweight and is just a big dog, she added.
With a 59in chest some body builders would envy and a 29in neck, Samson also wears pony coats to protect him from the rain.
Mrs Woods said it was visitors to their home who made them realise Samson's expansion.
"Because we live with him, we didn't really see that he was growing so much.
"But people kept saying he was getting larger and larger."
Mrs Woods says Samson has been "very unsettled" by the media interest and so she and her husband have ruled out any more photographs or filming.
She added: "He's a very placid, laid-back dog and I don't think he liked being ordered about - he just likes the quiet life."