His golf balls, that is.
In 1891, Old Tom - probably the most important figure in golf history - was in Ireland for an exhibition of golfing. To warm-up, he practiced next to Lough Salt in County Donegal, hitting 20 balls into what is called Donegal Lake. And those ancient gutta percha golf balls, struck by Old Tom Morris, are, presumably, still down there in the silt at the bottom of the lake.
And a team of divers is looking for them. The Independent newspaper of Ireland reports:
At the end of the 19th century, four-times Open champion Morris was in the county to design the Rosapenna golf course.
Local historians record an incident where the Scottish golfer stopped off at nearby Lough Salt to practise his swing.
Now diver Gus O'Driscoll and four members of the Delta Specialist Diving Club are hoping they can find the rare golf balls.
"There are literally thousands of balls at the bottom of Lough Salt because stopping off to hit golf balls there has been a tradition going back to Morris's time," he told the Irish Independent.
"We have recovered some golf balls from the early 1900s but we haven't located Morris's golf balls as yet."
If found, how much are Old Tom's balls worth? About €20,000 each, according to estimates.