It’s a foot of a huge statue of Marcus Aurelius, who ruled in Rome from 161–180 AD.
It was found in Turkey during an archaeological dig in 2008. The statue was likely toppled from an earthquake.
You’ll notice his second toe is longer than his first, which is called Morton’s Toe. It was a sign of prestige and beauty and was often applied to statues, even if it wasn’t the case in real life.