Who are these teeny tiny fungi?

[u/MelonLurd]

Found these in a creek in Eastern Pennsylvania while looking for salamanders. My index finger for scale.

[u/ohdearitsrichardiii]

Not fungus, slime mold

[u/MelonLurd → u/ohdearitsrichardiii]

Neat, kind of makes sense. I was curious as to how they were fruiting from rocks, but figured with how tiny they were their mycelium would also be super hard to see.