Mesmetron

Mesmetron is a Fallout 3 weapon that is used in the quest Strictly Business. When used on the specified quest NPCs, it puts them into a hypnotic stupor, allowing the player to rob and enslave them(by putting a Slave Collar on them) and send them to Paradise Falls. It also appears to work on some other NPCs, but often simply sends them into a berserk frenzy in which they become hostile towards the player and every other NPC in the area. Occasionally, the victim will run several steps before their head explodes.

Trivia
The Mesmetron is similar to the Persuadatron from the Syndicate game series ( I used to love that game :D, BlacKRaiN_666), going as far to even being named similar. The Persuadatron on the other hand allowed complete domination over a victim without the need of a Slave Collar.

The idea of an exploding Slave Collar is featured in quite a few movies and novels. Such as:

The Running Man where people are held captive through the use of collars around their necks that can be triggered to explode.

Another film making use of an "exploding collar" to make prisoners obey is Wedlock. Also widely known as Deadlock.

Exploding collars are also used in the movies Battle Royale and Battle Royale 2: Requiem, and in the Anime movie Cyber City Oedo.

The Playstation 2 game Ratchet: Deadlocked/Ratchet: Gladiator (outside the US) features exploding slave collars. In co-op, these explode when the two players are too far away from each other for ten seconds.

Appearances
Mesmetron appears only in Fallout 3.