Mushroom Help

[CoralReefer13]

I have a regular green mushroom on a frag plug. Can someone tell me what the substance is growing on the plug underneath the mushroom? It is like a white sponge/foam. It almost appears the same texture as the mushroom. Thanks for any help.

 

[James M]

sounds like a sponge but need a pic

 

[CoralReefer13]

Hope this helps. Looks like a white foam, but it feels light and sponge like. Keeps growing bigger and bigger. Thanks