Riddonkulous

Add an s to my end, and I’m an OG cartoon character from the Stone Age. Add a sandy destination to my end, instead, and I become a world-famous golf course in the Golden State. If I’m trapped inside your shoe, I’m endlessly annoying. Flat versions of me are perfect for skipping across water. By definition, I measure somewhere between four and sixty-four millimeters in size. What am I?