Could be hydroid polyps or similar. Best you contact taxonomists from the Museum. In Germany this would be either Senckenberg (Frankfurt or branch in Wilhelmshaven) or the Museum Alexander König in Bonn. Also MNL in Leiden could be in the position to help.

A species of Alcyoniina (Octocorallia) without any doubt. Sclerites are clearly seen in your picture, with long spindles arranged longitudinally in the trunk of the colony, and in chevron (points) in the polyps. Perhaps Paralcyonium spinulosum according to depth and colony structure, but the sample should be carefully examined.

See: Weinberg S (1977) Revision of the common Octocorallia of the Mediterranean circalittoral. 2. Alcyonacea. Beaufortia 25: 131–166

 Good luck!

I agree with Alvaro. It is an octocoral for sure. Probably Paralcyonium but only a clear analysis of its sclerites could give more clues about the species. Oscar Ocaña from the Museu of Ceuta has some expertise on the ID of that geographical area. Despite retired Leen van Ofwegen worked with Alcyoniidae and Nephteidae and may also help regarding knowledge of specific taxa.

Thank you all for your helpful answers.