An international network of/for intelligent organisms
Hmm, it would surprise me very much if a slime mold could survive inside any part of the human body. Their natural ecological role/niche does to my knowledge (To be fair I have limited experience with different slime molds) not involve other organisms than bacteria and fungi. As such I do not expect them to have any adaptations that would allow evasion of the immune system or ability to survive within the human body with its rather different conditions from forest floor and such.
Based on the video, I would say it isn't slime mold. In the video, it is stretched to peel it off which is something I have never seen a slime mold do before (they usually just break apart). I agree that slime molds would probably struggle in the human body but I don't know for sure.
That just looks like the kind of mucous you get with inflamed mucosal tissue, I don't do gut but I've spent a fair bit of time picking the stuff off uterine biopsy samples ( lovely job for a Monday morning) . Even if they could make it through the stomach, myxomycetes are aerobic organisms, there's a distinct lack of oxygen in there - the only reason it looks roomy and spacious is the co2 they pump in before shoving the camera up.
I do have an endoscope if anyone wants to experiment
Imagine the ethics forms you would have to fill out to be authorized to raise slime molds in the gut.