An imperfect fungus
Some fungi produce structures specifically for the production of asexual spores. These structures look nothing like those that produce the sexual spores. These so called "imperfect" forms are known as anamorphs.
This is the anamorph of the powderpuff bracket fungus Postia ptychogaster that fruits on stumps and logs of rotting conifer wood. I had seen these only once before.
The sexual stage, the teleomorph, looks like a regular bracket fungus with a white projecting shelf and pores beneath that release the sexual spores.