I reckon it is a puffball but not that species. Some creature has been gnawing on it.
Very gradual dark staining
Fruiting despite dry conditions
Clusters of these were in a loose 3metre circle. Another similar, larger circle of the same thing not far away. Both in leaf litter and mulch under eucalypts. The majority of the caps were smooth on top, unlike this one.
Several clusters amoungst loose dry ground leaves. No grass. 5cm-10cm apart. Dry/,aged. Moist base. Gills are stable.
Mushrooms in parkland