This sand dune Nickerbean has thorns on its stems .Plants are erect or spreading and vine-like. If erect in habit, they may attain a height of approximately 4 feet; if reclining or spreading, and using other vegetation for support, the stems may grow as much as 18 - 20 feet in length. Sharp spines cover the stems, which may grow to 2 or more inches in diameter.
... and thorns on its seed pods.
Beach snail (smalller than photo) leaves a trail in sand.