A self-portrait of Leonardo da Vinci is covered in 'mould' and will likely prove impossible to repair.
The precious red chalk drawing of the elderly, slightly-grumpy looking genius was sketched in the early 1500s.
But after being accidentally exposed to sunlight when being framed for an exhibition in 1929, the picture has now deteriorated to the point where it's developed red blotches, stains and fungi which were visible the only other times it has been removed from storage to be shown to the public, in 2006 and 2011.
A bad case of acne? Da Vinci's self-portrait is in a bad way
Now a series of studies by experts have confirmed that the picture's condition is so bad any attempts to restore it would risk destroying it.
The head of Italy's Central Institute for Restoration and Conservation of Archival and Book Patrimony, Maria Cristina Misiti, said:
"It scary to deal with a work of art of this magnitude and uniqueness. We will continue to study it, to diagnose it. Everyone agrees on that."
The decision on whether to attempt the restoration will be taken by the Royal Library of Turin, the restoration institute, and scientists.
If Da Vinci's self-portrait doesn't survive its exposure to the elements, it won't be the first famous artwork to have been accidentally ruined.
In 2010 a woman in New York fell into The Actor (1904) by Pablo Picasso, causing a six-inch tear in the canvas. Luckily for her she wasn't made to compensate it's estimated worth of £83m.
Four years before that, a different Picasso was damaged by its owner Steve Wynn, an America casino owner, who accidentally plunged his elbow into the painter's depiction of his mistress Marie-Therese Walter - leaving him with a £57,500 repair bill.