Hilarious moment on the links Wednesday ... Tony Romo was scared crapless by a fake snake -- and it was all because of a prank played on him by ex-NBA star Deron Williams!
Romo -- a near-scratch golfer when he's not broadcasting NFL games -- was out at Maridoe Golf Club in Texas with Williams when Deron decided to have some fun.
The former Utah Jazz superstar laid down a rubber snake by Romo's golf cart ... and fired up his phone's camera.
What happened next was hilarious .