We had a plague of these a few years ago, all you can do is keep digging them out along with the mycelium. We don't know how they started off with us as the area they first appeared in hadn't had any new compost or mulch applied to it.

Poor you, put on disposable gloves as you need to remove each one with the surrounding soil that has any white bits and dispose of carefully. If you can let the sun get at that area to dry it out and apply a fungiside. If you have put bark on this area you might want to remove it as that keep the area damp and is not helping. Some advocate pouring bleach over them but this does not sound the right site for that.

wouldn't expect there to be bark on a rockery... but who knows. We didn't apply a fungicide just kept removing and eventually they stopped reappearing.

I would not normally expect bark either MG but there is a rockery down in the village that they have smother in bark so just thought I would mention it!

Good grief... grit would be my choice of dressing for a rockery but it takes all sorts.

It does that

They're common in woods in the south-west. We used to get several every year in our last garden. I used to extract them including the underground "egg", double wrap them & put in the outside bin.

If you can bear to look at them through your watering eyes they're really quite remarkable - an incredibly light, rigid structure that pops up so quickly!

We quite often could smell it but not locate it in the dense bushes. Then I'd sit on the steps nearby and watch the flies to see where they headed and reappeared from. A very calming experience.