A coralline red seaweed washed ashore from deeper waters. The jointed stems contain lime/calcium absorbed from sea water. The bleached, calcareous skeletons of Corallines are commonly found washed up on beaches.
The ID created a challenge. Males of this species, as featured in MOV 2 shows a white tuft end to the abdomen. This one has an orange colour tuft as well as a black upper body and stripes on the underside of the body. May eventually be found to be a different species. It got knocked off the sheet by a larger insect and played dead long enough to get a photo of the underside. Two additional images included to show the features.