These little white things just show up on my laminate floors. Initially on kitchen floor and just now found this one on the base of my desk support (photo on far right). It is crusty, friable, bumpy and pure white. They seem to appear spontaneously, sometimes minutes after cleaning. . This is the largest I have found (~ 0.75 cm). It looks like a photo on texasmushrooms.org. If so, what can I do