I Removed A ‘Stone’ From The Bunker But It Was A Clump Of Wet Sand. What’s The Ruling?

A 'stone' in the bunker turns out to be a clump of wet sand...

You’ve played what looked like an absolute beauty of an approach into a difficult green. It was flying straight at the pin!

But you got the clubbing wrong and it’s come up 10 yards short in a greenside bunker.