Black Moldy Marks on wood inside wall under upstairs bathroom... What is this?

[jsmlee1207]

Hello, so I saw a slight crack in my drywall ceiling with water marks, which was located below an upstairs bathroom, so I decided to make a small hole and put a camera through to look inside.
I noticed that an area nearby with very black moldy marks. Is this mold or what can this be? Please help! Links are below to the images.. Thank you.

https://imgur.com/MJ8D48T

https://imgur.com/fR6ECOV

 

[oldVermonter]

If indeed it is mold (seems likely), I suggest checking out this website:

Mold | US EPA

Learn about mold and how to control it in the indoor environment.There is no practical way to eliminate all mold and mold spores in the indoor environment; the way to control indoor mold growth is to control moisture.

www.epa.gov

 

[Sponsor]

 

[WorthFlorida]

Spray paint or adhesive from the factory. Wipe your hand across it. If it mold you'll see it come off.

 

[Jeff H Young]

I am having trouble with the picture the stairwell isnt dry walled or dry wall was ripped open? some of the black looks normal other looks suspect maybe its blown up real big in pic just looks hard for me to tell. It should be obvious but I suppose for 10 bucks get a kit and test it, because I cant tell in the pic