Does anyone know what this is???
Looks like a mold..
It looks alot like mold to me.
Did you recently top dress with a dry amendment or water in/dose some myco boost or beneficial bacteria? Are you feeding bottle or doing living soul soil?
That looked to me like beneficial saprophytic fungi that are part of a normal myco boost blend. The are breaking down organic matter and won’t hurt the plants. Make sure you are not getting them too wet. That type of fungus likes it moist. If you did not top dress dry amendments, or recently do microbe boost it’s a sign you are running a tad too wet.
Other wise completely harmless.
If it’s bugging you mist it with some h202 lightly or sprinkle a very light dusting of cinnamon over the soil. It will knock back what you are seeing on the surface. If you can let it ride then I would let it ride.
Happy growing