Did the Undertaker invent the Tombstone Piledriver?
The Tombstone Piledriver is a modified version of the Belly-to-Belly/Reverse Piledriver, which ends with the person falling to a sitting position rather than landing on their knees. Undertaker is not the first person to land on his knees with the manoeuvre or call it the Tombstone. Notably Andre the Giant used it as a finishing move occasionally, although Undertaker is certainly more well known for using it.