Dad Gary, 37, of Plymouth, said: "Thomas was holding his food normally and the gull came from nowhere out of the sky.
"I didn't really know what was going on, I just heard my boy start to shout.
"He had blood all over his hand, and his doughnut was on the floor.
"The seagull was still on him when four other gulls then joined in. It was terrifying."
Gary, who works at the Royal Mail, added: "I've always dismissed it when people say they've been attacked by seagulls.
"It sounds ridiculous, I thought it was just silly stories.
"But they were so vicious. I was so shocked and I'm not too sure what can be done to stop this happening to people in such a busy area.
"I'm not going to give my children food outside anymore. People should be aware."
Since the attack several others have flocked to social media to report being attacked by what they claim is one particularly savage bird.
Charlotte Turner was also attacked in the same spot when a bird landed on her shoulder and stole her cheeseburger.
"I won't eat outside since it happened," Charlotte said.
"I'm genuinely traumatised."
Jon Bishop said he was also attacked outside the McDonald's restaurant, where a seagull hit him on the back of the head.
The gulls can be found in seaside places all year around and have proven to be an issue in the Plymouth area for many years.
Attacks in Devon and Cornwall have become increasingly common in recent years.
Several other youngsters have been hospitalised and In 2015 a pet dog was attacked and killed in back garden in Newquay.
And last year one of the angry birds swooped into a Truro supermarket - causing terrified shoppers to flee.
Plymouth MP Oliver Colvile is currently helping lead a call for action in Parliament against the menacing birds.
Several solutions have so far been tried or proposed including producing educational newspapers to wrap fish and chips in St Ives.
And earlier this month the Mayor of Truro called for anyone caught feeding seagulls to be given on the spot £50 fines.
Traditionally, the species should be found at sea.
However in recent years the birds have relocated to urban areas and experts have speculated the reason for the migration is food.
Growing up to 66cm in length and weighing over 1.5kg the birds are one of the largest and nosiest.
It seems the seagulls have taken it upon themselves to grab food in residential and commercial areas.
According to the RSPB website, seagulls are misunderstood by the general public and attack when trying to protect their young.
They suggest the way to prevent the urban gulls from causing harm is to 'prevent Street littering, and make public bins and business waste containers gull-proof'.