growing on hardwood log (prob rowan or birch) in log pile. about 10mm long
Caution: Do NOT use iSpot to identify fungi to eat!
Some fungi are very poisonous so a mistaken ID could have serious consequences.
No interactions present.
If I remember correctly, I think the spores would be needed for a certain ID as there are a few that look superficially similar.
If it is any help; there is a good image and description of Slime mould in Collin's 'Complete Guide to British Mushrooms and Toadstools' p335. Stemonitis fusca - fruit body comprises dense clusters of thin dark, hair-like strands bearing sausage-like spore masses; found on dead wood.
Lat/Lng: 56.9, -2.3
OS grid ref: NO8387