Cerberus

Cerberus is the Mister Gutsy model robot patrolling the ghoul city of Underworld. If the Lone Wanderer speaks to him, he or she will learn that he is not fond of his role in protecting the ghouls and that a combat inhibitor prevents him from killing everyone in sight. A player with the Robotics Expert perk can remove Cerberus's combat inhibitor, the underworld residents will become hostile as Cerberus goes on a rampage, as well as a karma loss. However a critical hit on the Inhibitor will produce the same effect minus the karma loss and the Ghouls will still be friendly toward you. One of the Ghouls can be heard saying, "Well, that's the end of that." Please Note Cerberus does not succeed in his rampage and is brought down quite easily by the citizens of underworld, though if the player is wanting to kill everyone in the underworld for what ever reason, disabling his combat inhibitor can help you take down the underworld.

Appearances
Cerberus appears only in Fallout 3.

Trivia
In Greek Mythology, Cerberus is the 3-headed dog who guards Hades and the Gateway to Underworld. Through dialog, Cerberus will agree with the player that he is the "Guard Dog" to Underworld. (And he also has three "Heads.")

Quotes

 * "Atten-shun! Civilian on deck."
 * "Go Underworld! Go Ghouls! Yay!"
 * "...Damn this pansy zombie programming..."
 * "Closing dialog system."
 * "Personally I think they're a bunch of rotting zombie-maggot farms, and I'd sent them back to Hell if I could, DAMN THIS COMBAT INHIBITOR!"