I just stumbled on this 2006 patent from inventor Donald Scruggs for a “Easy inter burial container.” The name in no way describes what this really is: a coffin that doesn’t need a hole dug in advance, because the entire coffin can be drilled into the ground vertically.
Here’s the description from the patent:
A series of burial containers having means by which they can be pressed, agitated, screwed and or self bored into a receiving material, provide low cost interment methods with hermetic sealing, security locking, plaque and memorial markers and built in flower and flag receptacles. They greatly reduce excavation labor and burial costs while providing the respectful funeral services currently practiced. They also decrease the land space required for each burial and provide for burials in normally unused areas within the cemetery, greatly increasing the number of burials possible in each cemetery. The apparatus and methods can be used for all sizes of humans and pets as well as for underground storage of equipment, supplies, food, water, fuel or other such material as may be required to be made