• Mentioned in the Diary Log of Dr J. Welsh.
  • He seems to be working in league with Dr Welsh against Dr Horn.
  • Dr Stone is the in-game alias for Anthony "OnboardError" Stone, a level designer on Black Mesa.
  • OnboardError has a personal website at (which is hosted on the same server as However, nothing ARG-related has so far been found on the site.
  • A few posts OnboardError has made in the forum thread seem to indicate that he was involved in the placement of the hidden pizzas and Biodome Complex insignias in Black Mesa. [1] [2] [3]