Excuse me, what is this??

This started with small black spiky stuff coming out of the part of the shrimp wood which was protruding out of the tank (it never grew beneath the water, always above it). I usually kept removing it every week during tank maintenance and it kept coming back.. But this is a freaking surprise! 😅 it seems to have grown 3 mushrooms overnight! I saw something white in the spiky stuff at night, but didn't expect this surprise in the morning. I had posted regarding the spiky stuff once on reddit (will attach a link here if I can edit or will comment the link) and one of the redditors mentioned he had the same issue but in a red colour and that it was mycelium.. but nothing much in detail. Has anyone else encountered it? Is it safe to the tank/fish? Is it safe to touch? How do I get rid of it? And prevent it from coming back?