Benny is the first major villain encountered in Fallout: New Vegas. He is recognizable by his black and white checkered tuxedo and is voiced by Matthew Perry of Friends fame.
At the very beginning of the game, he ambushes the Courier outside of the town of Goodsprings, shoots them in the head, and buries them in a shallow grave. However, the Courier survives because they are rescued by a scavenger Securitron robot named Victor and then nursed back to health by Doc Mitchell of Goodsprings, and then sets out to find the assailants and take revenge. After following the trail through several locations, the Courier tracks down the members of the Great Khans gang who were with Benny during the shooting, and learns that he is the leader of the Chairmen, one of the gangs controlling the Casinos of the New Vegas Strip, and is at the Chairmens' casino "The Tops" right now. Alternatively, the player can skip all this storyline and go directly to New Vegas to confront Benny, if they already know how from personal experience.
When the Courier enters the Strip and confronts Benny in casino floor in The Tops, he is shocked and asks to discuss things privately in the hotel's private suite, which he gives them the key to. When the player goes to the room, Benny is nowhere to be found and tells them over the intercom that it's a trap, and a group of his goons show up to kill the player. After they are dealt with, the player can use the intercom again, and Benny says to be careful and thorough when cleaning the room, believing he is talking to the people he hired to get rid of the Courier's body. When he realizes that the Courier has survived yet again, his response is simply: "What the fuck?!"
After returning downstairs the player is told by the other Chairmen that Benny just fled the Strip, and the Courier investigates his living quarters for clues to where he might have gone. There, they find "Yes Man", a Securitron robot who Benny reprogrammed to help with his plans... only he accidentally made it so Yes Man would have the same loyalty for anyone who wanted to do the same! Yes Man reveals that Benny had been plotting to overthrow Mr. House and take over New Vegas using the Platinum Chip, which the Courier was supposed to deliver to House in the first place. Upon first entering the Strip, the Courier had previously been invited into the Lucky 38 where House resides and instructed to recover the Platinum Chip from Benny for him. But now Yes Man offers to help the Courier kill Mr. House and take over the city for themself.
Whether the Courier chooses to listen to House and Yes Man, they are told that the secret bunker where the Platinum Chip needs to be used is located directly under Fortification Hill, the main base of Caesar's Legion. At the Fort, they find that Benny had tried to sneak in so he could use the Platinum Chip in the bunker, but was discovered and captured by the Legion. He is tied up in Caesar's personal tent, and Caesar, who also wants the Courier to help him take over the Mojave, gives them the Platinum Chip he took from Benny but tells them to destroy whatever is in the bunker.
Caesar also lets the player kill Benny however they want, by either beating him to death in the tent, fighting him "fairly" in the Legion arena, or crucifying him. Benny at this point is prepared to face death with honor (unless you crucify him), but if the player really wants to there is an option to forgive Benny and set him free. If you do this he is extremely grateful and promises never to get in the Courier's way ever again. However, for him to get past the Legion alive, you have to either give him a Stealth Boy to make him invisible or murder the entire Legion. Either way, if Benny survives his escape, he disappears from the game and is never seen again.
It should be noted that the series of events described above is only the default, most involved path of dealing with Benny. It is entirely possible to go directly to New Vegas from the starting point without doing any quests at all, then kill Benny on sight in The Tops without even talking to him (of course if you do this you'll have to fight all the other Chairmen). Additionally, if you are a female character you can seduce Benny to have sex with you, then have the option to kill him in his sleep.
An encounter that was removed from the final game would have seen Benny stopping to Complete Monster status, by attacking the player again after being spared at the Fort. This was likely removed because it made the character too evil and would have justified murdering him at the first possible opportunity, and also because it would have left no way for him to survive the game.
Fallout: New Vegas