A six-year-old boy has discovered a tooth belonging to a megaladon shark dating back more than three million years.
Sammy Shelton made the amazing find while looking for shells on Bawdsey Beach in Suffolk earlier this month.
Megalodon is an extinct species of mackerel shark that lived between about 23 and three million years ago and was as long as 20m (65ft).
Sammy astounded his classmates by brining the four-inch tooth into school for show and tell.
He has been sleeping with the tooth next to his bed ever since he found it.
His father, Peter Shelton, 60, said: "People have said it's a once-in-a-lifetime discovery.
"Really we were looking for interesting shells on the beach but instead we got this megalodon tooth.
"It was huge and very heavy. I knew what it was but it wasn't until I took it to others looking on the beach that I realised the significance.
"There was one guy down there who's been looking all his life for a megalodon tooth and never found anything of this size."
Ben Garrod, professor of evolutionary biology at the University of East Anglia, has checked pictures of the tooth and said it was once of just a handful found in Britain each year.
Sammy has been awarded an "explorer" badge from his local Beavers group for finding the tooth.
He is eager to return to the beach to find more fossils.
"At the moment he's keeping it by his bedside," his father said.
"He's taken it into school and to Beavers to show his friends. Sammy wants to go back again. He likes being outside."
Watch: YouTuber finds shark fossil tooth on beach