The skull of a 66-million-year old Triceratops is expected to raise almost $2 million at auction.
Known as Lung Wong, or the Dragon King, the fossilised item is said to be the world's largest intact dinosaur skull, measuring 9.2ft (2.8 metres) long.
The auction is open now and the fossil is being sold by Hong Kong-based experts at Evolved.
The last time something of this size and quality came to market was when a Tyrannosaurus Rex fossil named 'Sue' was sold for £5.6 million ($8.5 million) in 1997.
The rare Lung Wong fossil was first discovered in 1992 when rancher Ray Novakovich in Glendive, Montana reportedly found the tip of one of the dinosaur's horns.
Owing to its size and a lack of resources, though, it wasn't excavated until 2003 - and since then is said to have changed hands a number of times.
It has also been restored and preserved into its current condition.
The skull is more than 95 per cent complete bone, is 9.2ft (2.8 metres) long, 5.2ft (1.6 metres) high and 4.6ft (1.4 metres) wide.
In a statement released by Evolved, the firm said that a fossil 'of this magnitude and quality is only very rarely available for private sale anywhere, and never before in Asia.'
However, the experts have not revealed when the auction closes and MailOnline has contacted it for more information.
The name of the fossil is inspired by the symbol of 'strength, good fortune and longevity' in Chinese culture - the dragon. The size of the skull apparently also suggests it might be an entirely new species.
The largest previously recorded Triceratops skull measured 8.2ft (2.5 metres) long, but the creatures' skulls were said to average at around 7ft (2 metres).
'If this [theory] is confirmed, the owner will be entitled to name the species for posterity,' the group selling the skull added on its official website.
However, some experts have bemoaned selling such a prized fossil to a private benefactor, rather than placing it in a museum.
'Commercially sold fossils kept in private collections cannot be studied by paleontologists because they can only publish research on fossils stored in museums or similar institutions,' said Dr. Michael Pittman, a research assistant professor at the University of Hong Kong, reported Shanghaiist.