A mum who thought the family dog - an XL bully - was "lovely" until it attacked her six-year-old son, has urged the government to adopt tighter laws.
The mother, who has asked not to be named, lives in Carmarthenshire, West Wales. She has had an XL bully for a couple of months.
The UK government announced last week that the breed would be banned in England and Wales from the end of the year.
There was "not a single sign" the dog could act in that way, she told Sky News.
"There was no signs that she was aggressive towards children in any shape or form," she said.
"She's very protective of people walking past the house, but outside of the house on walks, the street would fuss her, the kids in the village would all come and hug her. I thought she was lovely."
She said her concern now was "what was happening before [she] had her".
When the incident took place on Saturday, she was cooking in the kitchen and was "finishing off dinner".
The attack meant her son had to have butterfly stitches on his face and suffered heavy bruising.
"I've heard this growl and I've just ran and as I ran she's pinned him on the floor. I've gone on top of her, put my arms and legs around her and turned my body to throw her off," she said.
"Honestly, I don't think she would have stopped until he was dead. I really, really don't."
Knowing what could have happened to her son has been difficult.
"To think that I could have just been out doing the washing or I could have been speaking to someone outside the front or anything," she added.
"There was no warning signs. It wasn't like she was ever funny with the kids. She loved those kids. I would never risk my children's life like that for a dog."
Before the incident, the woman had been a critic of the UK government's ban on XL bully dogs.
"We're like, 'It's nonsense, it's nonsense', until you actually have to pull a 50kg dog off your son and I think then we start thinking," she said.
The dog would now be put to sleep after the incident, the woman confirmed.
She said the ban was not "fit for purpose" as it would not "protect the children that are at home with the dogs".
"Every dog owner in this country should have to have a licence, every dog should have to undergo some sort of training so that somebody other than the dog owner has witnessed that dog and seen the type of temperament they are," she added.
"I think there should be a lot more legislation in place."
Sky News has asked the Department for Environment, Food and Rural Affairs for a response.