What are these spots

[andy123]

These spots appear then vanish and keep coming back on plaster/painted wall.
Want to know what it is, why it happens and how it can be resolved.
It is upstairs bedroom, that is attached to next doors house.

 

[Monkey Boy]

If you lightly draw round the spots (with a light leaded pencil 2B usually about somewhere rather than HB pencil) do the spots reappear in exactly the same places? Does your roof above leak? Why say the upstairs bedroom is attached to neighbours house as if that is an abnormal set up? Is it?
Also begs the question what goes on in that room?

 

[andy123]

If you lightly draw round the spots (with a light leaded pencil 2B usually about somewhere rather than HB pencil) do the spots reappear in exactly the same places? Does your roof above leak? Why say the upstairs bedroom is attached to neighbours house as if that is an abnormal set up? Is it?
Also begs the question what goes on in that room?

Roof above is fine.
Was referring to it not being an external wall.
It’s where my 3 year olds sleep.

 

[themucky1]

Probably gonorrhoea then

 

[johniosaif]

It's often the mushrooms from the woods

 

[theshed]

Get a can of stain block and give them a spray. It should stop them showing through.

 

[smoother09]

Crop circles? Could be ET trying to call home

 

[Cockney]

Furiously wanking teenager on the other side of that wall. Seen it happen before up north somewhere!