Brain Puffball (Calvatia craniiformis, 头状秃马勃).
Another calvatia growing on Yuelu Mountain during this hot humid season. I don't see them on the lower slopes but at higher elevations these ostentatious wrinkled brains seem to be everywhere. This one shows burrowing holes made by small beetles, which frequently make them a summer residence, before they crumble into spores and dust.
