Strange circle on plaster wall

[KarenCnuk]

Untitled

• KarenCnuk
• 8 Mar 2014
• 1

Untitled

• KarenCnuk
• 8 Mar 2014
• 1

Untitled

• KarenCnuk
• 8 Mar 2014
• 1

Hi, could anyone help me identify this strange circle on my bedroom wall please?

I've noticed it yesterday at the lower part of one of the walls. On the other side of the wall, there is a bathtub, which is fully functional but rarely used.

The circle itself, as you can see, is almost perfectly round. It feels a little bit cooler than the rest of the wall.

I have no idea how long it has been there. I've just rearranged some furniture, right before spotting it.

Looking forward to your comment. And thanks a lot in advance.

Karen

 

[noseall]

It's similar to a crop circle only this is a wall version.
Looks like a grease stain or residue from a sticker to me.

 

[JohnD]

water leak.

 

[roy c]

Could be one of the "dabs" showing thru on a cold/damp wall if is a dot& dab wall!!!