What amazing images. Never seen anything like it! Were you able to take a photo of the underside of the fungus? Was it smooth, gilled or some other? Any additional information would be useful.
Unfortunately I didn't think to take a photo of the underside. I have seen something similar amongst the Atlas photos for fungi but the photo is more domed. I did wonder whether my fungi was just a more advanced version.
Oh for an image from the side, even slightly to the side! Do you remember how tall they were and if they had gills? What sort of vegetation were they growing in?