Help with identification of a possible fossil found on the beach Viana do castelo Portugal.

[Tiagoi]

 

Hi everyone,

I recently found this object on the beach of Viana do Castelo in Portugal, buried in the sand. It has a very peculiar structure that resembles teeth or a jawbone, with repetitive segments that look like fossilized teeth. I'm unsure if it's a real fossil or just an unusual rock formation. 

Here are some pictures of it. Any help with identification would be greatly appreciated!

Thank you in advance!

 

[Rockwood]

Quartz vein. Often formed as volcanic intrusion.