Doctor 0

Doctor 0 is a pre-War scientist operating in Big MT in 2281.

Background
Doctor 0 is a pre-War doctor that became a think tank to continue his work at Big MT. Doctor 0's scientific specialty is in robots, both in construction and deconstruction. He also has a large hatred for Mr. House and his founded company, RobCo Industries. As a result, he built Muggy with the intent of mocking House's Securitrons. He also recognizes the Pip-Boy latched around the Courier's left wrist and would have forcefully removed it out of spite, if he still had hands.

Upon dialogue with Dr. 0, the Courier discovers that his name is not Doctor O, but Doctor (Zero), and everybody has been reading his name wrong.

Quests

 * Old World Blues: If Klein cannot be convinced otherwise, 0, along with 2 other members of the Think Tank, is needed to convince Klein to give up trying to escape Big MT.
 * Picking Your Brains: After completing Welcome to the Big Empty, the Courier needs to talk to 0 and the rest of the think tanks to complete this quest.
 * Welcome to the Big Empty: The Courier has to talk to 0 as with the rest of the think tank to complete the quest.
 * What's in a Name?: The Courier must have 9 Intelligence or the Math Wrath perk in order to help him with his name problem. The player character will suggest adding a slash through the zero to differentiate between the zero and the O, or, through the correct dialogue, convince Dr. 0 to keep his name as “O.”

Other interactions

 * If the Courier passes Barter skill checks during their initial dialogue with the Think Tank, he will give them 50 caps upon request once per day.

Effects of player's actions
If the Courier has helped out 0 with his name problem, and they do not have a 100 in Science or 85 in Medicine to convince Dr. Klein alone, 0 will side with the Courier in convincing Klein to back down.

Appearances
Doctor 0 appears only in the Fallout: New Vegas add-on, Old World Blues.

Behind the scenes

 * If the Courier is working for House, 0 can be informed about it. His subsequent quote is a reference to the comparison of Nikola Tesla and Thomas Edison where Tesla died poor and lonely and Edison died rich, with Dr. 0 hoping that House would share the fate of Tesla. If House is dead, this too can be mentioned, by telling him that he "does not have to worry about House anymore." 0 will defensively reply that he was never "worried" about House and will then gloat about having outlived his rival.
 * James Urbaniak also plays the voice of Dr. Thaddeus S. "Rusty" Venture of The Venture Bros. Like Dr. Venture, Dr. 0 is very emotional, easily frustrated, and suffers from an inferiority complex as well a blatant ineptitude with technology, despite his claims to the contrary. Unlike him, however, Dr. 0 does realize he is inept as a scientist compared to his colleagues.
 * With the Wild Wasteland trait, one of his broadcast messages across the crater will be "Attention: Lobotomites. Do not neglect to wash the walking eye." This is another reference to an episode in The Venture Bros when Dr. Venture is seen washing the walking eye in front of a gathering crowd. With Wild Wasteland, these walking eyes also appear in the magnetohydraulics complex, although the Courier cannot interact with them.
 * Both names, 0 (number) and O (letter) are infinitely looping figures, which goes along with the naming theme of the Think Tank scientists.
 * Dr. 0's personality was originally intended to be a frenetic, hyperactive newscaster type, but was re-written to a "scientist-who's-aware-he's-not-brilliant-or-valued" after James Urbaniak was cast into the role. This can still be seen when talking to him before the main quest is finished.
 * An early version of the concept behind Dr. 0 was due to appear in the cut Fallout 2 location The Environmental Protection Agency. In this version "Hologram 00000" is the director of science for the facility and possesses Dr. 0's communication style.