Plasiacystis sp.
Early Ordovician (Arenigian)
Fezouata Formation
Mecissi-Zagora Region, Draa Valley
Morocco

Very strange flat-tailed carpoid. 31mm (83mm if outstretched) on 85mm slab. The unusual tail has led many people to suggest this creature is anything from a vertebrate to a cephalopod, but we found this paper by Prokop that seems to be an excellent match for this still undescribed echinoderm:

Prokop, R. J., & Petr, V. Á. C. L. A. V. (2003). Plasiacystis mobilis, gen. et sp. n., a strange “carpoid” (Echinodermata,? Homoiostelea: Soluta) in the Bohemian Ordovician (Czech Republic). Sbornik Narodniho Muzea, Serie B, Prirodni vedy, 59, 151-162.