Is that mold on the wall, strange spots?

I have discovered slightly grayish spots on my wall in the anteroom (not an exterior wall). Could these be mold? I don't know what else these spots could be. I tried to remove the spots with a dirt eraser as I usually do, but the spots remain.

Hmm why are these stripe/line-shaped, maybe cracks in the concrete?

What is behind it?
Did someone put something there?
Is it just this wall?
Are they getting bigger?

Hm why are those shaped like lines/stripes, maybe cracks in the concrete? What is behind it? Has something been placed against it? Is it only this wall? Are they getting bigger?

Hello, thanks for the quick reply. Behind it is a drywall. Nothing has been placed against it, in winter jackets are hung there, but I don't think they cause such strange streaks. It is only this wall, I have to observe whether the spots are getting bigger.

I hope and believe someone just hung up a dirty wet jacket there.

And with "mit was" I meant behind the wall, or what is running inside the wall is a bathroom above it.

I hope and believe someone just hung up a dirty wet jacket there. And by "with with what is behind" I meant behind the wall, or what runs in the wall, there is a bathroom above it.

Yes, that could possibly be the case with the jacket. But I am still surprised why I can't clean off the stains. Behind the wall is the children's room, where there are no stains. There is also no bathroom above it.

I guess it's a jacket. Sometimes closures, buttons, rivets, or the zipper of a jacket cause such marks. Depending on the material, it is an abrasion that no longer comes off the wallpaper.