does anybody know what this might be at all
where you found it?
It looks a lot like the corms of hardy cyclamen we've just dug up in a bed we're clearing of Spanish hyacinths. Not sure which one but the leaves have beautiful mottling and the flowers are small, dainty but very tough in autumn weather and either pink or white.
I shall be re-planting mine, along with the autumn daffs we've rescued, in another bed while I wait for any more unwanted Spanish bluebells to emerge in the original bed.
Like nut, we need to know size and where it was found. If small (eg 5mm) and on the soil surface then it's likely rabbit dung.