This object is a human skull-cup on a triangular base. It is crucial to a meditative technique called the “inner offering.” In that technique, meditators visualize themselves decapitated, “making a cup of the cranium, pouring all negativity into the cranial cup, boiling it into an elixir . . . and consuming its contents.” In this process, the flaying knife-chopper, with its curved blade matched to the skull’s concavity, is used to reduce the negativity to a fine puree. This alchemical transformation of negative forces into beneficial form is one of the Vajrayana’s most distinctive meditative processes.