Drivers on the M4 were shocked to see a 30ft-long dinosaur being pulled along by a van.
The 15ft-tall model of an allosaurus had been sold by the Dan yr Ogof caves attraction and was being taken to the home of the successful eBay bidder from Cwmbran.
The dinosaur - named Alun - has taken pride of place in new owner Jerry Adams' garden.
His £1,600 purchase has helped raise money for diabetes charity JDRF UK.
The caves' director Dan Owens said the Swansea valley tourist attraction had about 250 dinosaurs, with six new ones due to arrive before the summer.
Alun was sold to help make room for the new dinosaurs, Mr Owen said.
"It was right outside the coffee shop by the main door so it was probably one of the most photographed dinosaurs we have," he added.
Mr Adams said car drivers had already started stopping to look and passers-by were photographing themselves next to it.
He described it as "a big garden ornament", adding: "I have 12 grandchildren, three have autism, and it's a piece of garden furniture they can play with."
After finding out all money would go to charity, he said he had been determined to win the auction.