I've got these in the soil of one of our rose bushes. It showed up after I transplanted it. It is hard like a shell, seems to be growing. They are the white spore looking things.
That is wild. Looks like a growth for sure there. I never seen a fungus like that. Wow. Now I need to know. I have a few roses but they do not like my soil. I have a problem with a Rust thang. Other things do OK.