Sol 2867: Mars Hand Lens Imager (MAHLI)

 echinoderm fossil?

Sol 2867: Mars Hand Lens Imager (MAHLI)

This image was taken by MAHLI onboard NASA's Mars rover Curiosity on Sol 2867 (2020-08-30T02:31:22.000Z)

Image Credit: NASA/JPL-Caltech/MSSS

possible petrified feather star

https://commons.wikimedia.org/wiki/File:Barren_Island_feather_star_and_branching_coral.jpg