Enteridium lycoperdon

Q:

Any ideas please as to what this might be?  Appeared almost overnight soft to the touch.

A:

We think this is Enteridium lycoperdon, the false puffball, which is actually not even a fungus but a (delightfully named) slime mould. It’s not usually found on lime – alder is its favourite, but the tree certainly doesn’t look like an alder – but may have made an exception in this case!

It lives exclusively on dead timber and poses no threat to living plants in the garden, nor is it poisonous. It may spread quite rapidly over the dead tree, however.

Thank you for your unusual question!