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Last edited on March 27, 2014
by Jspoelstra
Mesmetron icon
skillEnergy Weapons
Attack statistics
1 (6.1)
1 (6.3)
DPS (reload)
0.6 (3.9)
crit dmg
crit % mult
effectChance of stun, frenzy or head explosion
Ammo & reloading
ammo typeMesmetron power cell
ammo cap.5
reload time
item HP100
questsStrictly Business
base id00004339

The Mesmetron is a unique weapon in Fallout 3.


The Mesmetron is an experimental pre-War "non-lethal pacification" weapon that was being tested in the months immediately preceding the Great War. It operates by sending a signal pulse into a human target's brain that scrambles higher-level mental functions, leaving the target extremely susceptible to suggestion. Still in its testing phase, the weapon was found to have the potential to trigger two undesirable side-effects: extremely increased aggression, or spontaneous cranial eruption.


When used on the specified quest non-player characters, 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 many other non-player characters (aside from quest related ones), but can simply send them into a berserk frenzy in which they become hostile towards the player and every other non-player character in the area. Occasionally, victims will run several steps before their heads explode.

It uses Mesmetron power cells as ammunition. You start out with 50 Mesmetron power cells. Grouse will also sell you additional power cells, but at the fairly high price of 200 caps for 10 power cells. This gives you the opportunity to make an additional 2500 caps every time you purchase more power cells (provided you successfully capture all 10 slaves). An additional 71 Mesmetron power cells can also be found in the underground lab in the Point Lookout add-on.


The Mesmetron can fire a total of 2475 waves, or 495 full cells, from full condition before breaking.

Using the Mesmetron

As previously mentioned, using the Mesmetron on a non-player character can have 3 different outcomes. These effects vary and are generally unreliable, so it is advised to save before using this weapon on anyone important. Due to the fact that using the Mesmetron is considered assault, it is advised to "mezz" someone while not detected (Stealth Boys and the Chinese stealth armor will come in handy here). Be aware that mezzing anyone who is already wearing a slave collar will cause the collar to malfunction and explode, killing the victim. Hostile non-player characters who were mezzed can also be turned friendly by being freed by the player (high Science skill required). An analysis of the Mesmetron's effects:

Mesmerize/Stun (50% probability)

A raider stunned by the Mesmetron

This effect stuns the target for a few seconds, during which time the victim will stand with his/her head swaying from side to side and it is possible to engage them in conversation. Some characters cannot be stunned, in which case the probability of the Frenzy effect is raised to 80%.

While in conversation, you will first have three options: The first convinces the character to allow you to take his/her things (by either telling them it's a magic trick, that there is a thief on the loose, that you think they stole something from you, or by just telling them to give you their things) and will open up the victim's inventory (even what he or she is wearing/using), allowing you to remove or add any item. The second slips a slave collar on the character (instantly netting the player negative Karma). The third simply tells the victim to "walk it off"; this will exit the conversation and make the character resume what they were doing (assuming you haven't made any onlookers hostile).

The second set of dialogue options is unlocked by slipping a collar onto the victim: The first is the "cruel" way to tell the victim that he is now a slave ("...your head will explode!"), the second option allows access to the slave's inventory, and the third option is a slightly friendlier way to inform the victim of his/her "new occupation" ("...nothing personal").

If the character is not spoken to before the stun effect wears off, he or she will become hostile to the player.

Frenzy (30% probability)

This second effect causes the victim to go into a state of frenzy, attacking anyone nearby (most likely the player), and causing all other characters to turn on them. The onlookers may also become hostile to the player if you are seen stunning the victim. This method can also be a reliable way to get rid of victims without attacking them or getting negative Karma. You can die from this, especially if one of your enemies has any high-damaging weapons.

Spontaneous cranial eruption (20% probability)

This final effect of the Mesmetron may not be the most useful, but is definitely the most spectacular. When victims are affected by the Mesmetron in this way, they will become hostile (and either run, stand still, or attack) for just a moment before their heads literally explode. This effect will instantly get the player negative Karma (if the victim was good/neutral) and make any nearby non-player characters who were not hostile to the victim become hostile to the player.



Weapon name (current weapon is highlighted)
Icon gun
Damage per attack (damage per projectile)
Icon damage
Damage per second
Icon dps
Bonus effects
Icon bonus effect
Attacks per second
Icon attack
Critical Chance % multiplier
Icon chance
Critical damage
Icon critical damage
Action Point cost
Icon action
Damage per action point
Icon dap
Weapon spread
Icon spread
Magazine capacity (shots per reload)
Assault carbine extended magazines
Durability (number of attacks before breaking)
Icon repair
Icon weight
Value in caps
Icon merchant
Value to weight ratio
Icon ratio
Mesmetron 1
1Chance to mesmerize(50%),
frenzy(30%), or head explode (20%)
Microwave emitter fo3pl
Gametitle-FO3 PL
62.1Ignores DR1.03x21003020.25375850062.5


The Mesmetron is given to you by Grouse, the Paradise Falls entrance guard, when you start the quest Strictly Business.

If you don't want to take the quest, you can obtain the Mesmetron by killing Grouse and looting his corpse. You have to kill him to obtain the Mesmetron, as it cannot be pick-pocketed. If you do this, you will not be able to purchase anymore mesmetron power cells from him, you cannot get slave collars, and thus you can't enslave non-player characters. You can still use the Mesmetron to frenzy or stun and rob non-player characters, however.


  • Robobrains have this weapon built in.
  • Enslavable targets are based on a faction list of 672 members, filled mostly with generic non-player characters. There's a shorter faction list of non-player characters who can always be mezzed, and this initially includes the four objectives of the Strictly Business quest and one generic leveled slave. Non-player characters set to essential may be immune.
    • A (possibly incomplete) list of enslavable non-player characters is located on the Strictly Profitable page.
    • After a non-player character is successfully mezzed they are added to a faction list that can never be mezzed.
  • To enslave someone you must have a slave collar. You can only have one collar and therefore only one person may be enslaved at a time.
    • It appears that unarmed (or disarmed) non-player characters are more likely to be enslaved by the Mesmetron. Attacking a non-player character's weapon or arms and then switching to the Mesmetron may be an effective technique.
    • Using the Mesmetron in V.A.T.S. can result in the Mysterious Stranger appearing if this perk is selected. The Mysterious Stranger will not fire on the target if they were successfully stunned, though V.A.T.S. will remain active for the usual period of time.
    • You can enslave a non-player character even if all of the slavers in Paradise Falls have been killed.
  • For each non-player character you successfully enslave:
    • Grouse will pay you 250 bottle caps per slave.
    • Enslaving anyone results in a loss of 100 Karma, regardless of how evil they are. As Three Dog exclaims, "the selling of live human beings is completely fucked up!".
    • A good way to offset the Karma loss (if you wish to be good or neutral), is to donate 100 caps to either Confessor Cromwell or Father Clifford.
    • The game will keep track of how many characters that you have "mezzed". You can access this information with your Pip-Boy.
  • Generic non-player characters (such as raiders) who are enslaved and successfully sent to Paradise Falls will not respawn.
    • Think about whether or not you want to interact with the character again before you enslave them.
    • Significant use of the Mesmetron in a specific area can therefore permanently clear that area of human enemies.
    • Additionally, enslaving a generic, hostile non-player character and then subsequently removing the slave collar will cause the non-player character to become friendly to the Lone Wanderer and companions (other alliances/hostilities, e.g. Brotherhood of Steel vs. Enclave, are not affected). This change persists even if the non-player character is killed and later respawns. Affected non-player characters will attack their usual allies (e.g. other Enclave members) if those allies attack the player.
  • From time to time a mesmerized and collared target won't make it to Paradise Falls. This causes the collar to be lost and as no slave was turned in, the collar must be re-purchased from the slavers. To ensure success fast travel to Paradise Falls if you are able to. (see bugs for more)
  • Followers may briefly attempt to attack a non-hostile non-player character once the non-player character is stunned; this is because the non-player character will temporarily become hostile to the Lone Wanderer before the stun effect kicks in.
  • "Mezzing" anyone in the Citadel Laboratory will automatically frenzy them (after the quest "The American Dream"). Witnesses will not turn hostile to the player.
  • If the Mesmetron is used on an unfreed captive and they are then freed, you will then be unable to interact with them again, except to mezz or kill them.
  • It is to be noticed that in third person the Mesmetron has no trigger.
  • The Mesmetron's light is visible when the stealth field of a Stealth Boy or the Chinese stealth armor is in use. It will not be on, however, if it is equipped (not unholstered) after the stealth field kicks in. (The light is always on during 1st person. In 3rd person, it can vary depending on how you equip it.)


  • pc
    Icon pc
    Freshly enslaved non-player characters will often be reported by Grouse to have died once the Lone Wanderer arrives at Paradise Falls. This is caused by a condition in the Mesmetron effect script which automatically moves the slave to Paradise Falls—indirectly marking them as dead in the process—once the non-player character is no longer being actively rendered. Aside from leaving the non-player character's immediate vicinity, numerous actions have a random chance to cause an non-player character to stop being rendered, including accessing the Pip-Boy, facing away from the non-player character for a certain period, or even accessing the game menu. [verified]
  • pc
    Icon pc
    Icon ps3
    Icon xbox360
    "Mezzing" characters who are seated, leaning on a wall or lying down may cause them to spin rapidly in place before their heads explode. [verified]

See also

  • Slave collar - Used to enslave non-player characters once they are mezzed.


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