Strange installation in an older bathroom is leaking - mold?

Hello dear people,

in my student room's bathroom, there is a strange mushroom-shaped handle on the wall in the shower, which drips and looks really disgusting.

Does anyone have any idea what its purpose is, and whether that is mold?

Best regards

That means I believe [Entlüftungsventil].

There are lime deposits because the pipe is rusted through. Whether there is additionally mold on them, I cannot exactly tell.

It is broken and must be replaced by the landlord.

Ok, thank you very much for the helpful info. :)

Hello Steamboat

A little tip!?
If something looks disgusting in my apartment, then I clean that thing. Because I don’t want disgusting things in my house.

Steven

then I'll clean the part

Well. You can give the OP the benefit of the doubt that the documented condition is far from "to be cleaned." The part is such a mess, only replacement helps.

Hi
The part is a pipe vent and belongs to the building's drinking water installation.
You can certainly fiddle with it a bit, but it won't become airtight because of that.
A replacement by a professional is necessary.

Olli