Question about disc

[Juanki]

Hi everyone!

I just bought a second hand blu ray disc of "Valentine's Day" and I found something strange I've never seen.



As you can check out the surface presents dirt (sorry!) but also some strange symbols like squares. That is present on a very long part of the disc even though it only gets pictured on the dark because of the light of the photo.

What do you think it could be? Is this disc spoiled? I still own the shop warranty so I don't know if the disc is kinda defective or if that is some evidence of rot. Is it safe to play for the player?

I appreciate any help on this issue. Thank you collectors!