There are some things you can't really change. Death for instance.
There are some things you could change with difficulty but would be unlikely to. Your last name for instance.
But there are a few things you and your heirs presumably have discretion over. Style of tombstone for instance.
This pun is clear and avoidable.
This one would be harder to avoid, perhaps they were just banking on very few people knowing that the Manes were ancient Roman spirits of the underworld, as recalled in the common Roman funerary inscription DM ( "for the Manes", or Dis Manibus for you non Romanists).