Essentially a bomb on legs, the Sentry Buster will detect any sentry that’s dealing sustained damage to the Robot Horde, then initiate its deviously complicated protocol: run at the offending sentry and explode.
— Mann Vs. Machine publicity blurb
The Sentry Buster is a specialized robot that appears in the Mann vs. Machine mode when a Sentry Gun has dealt significant damage to the robot horde. It appears as a large pair of legs similar to a Demoman robot, but with a large naval mine for a torso.
Once a defending Sentry Gun has dealt either 15 kills or 3000 damage to the robot horde (by default), a Sentry Buster will be dispatched; they do not appear under any other circumstances. Once deployed, the Sentry Buster will make a beeline for the Sentry Gun that triggered its appearance. Additionally, a voice response from The Administrator, the Engineer who built the targeted Sentry Gun, and in some cases, from friendly Heavies, Soldiers, and Medics are played to alert the team of the sentry buster's appearance. Upon reaching its target, it crouches and begins beeping. About 4 seconds later, it detonates in a massive explosion guaranteed to level the offending Sentry and just about anything else within approximately a three-Teleporter radius, including other non-giant robots around it. If giant robots are in the Sentry Buster's explosion as it detonates, the giant will only receive 600 damage.
While inattentive Engineers will be sure to lose at least their Sentry to a Sentry Buster, aware ones with a competent team can deal with it without too much trouble. Sentry Busters can simply be killed before they reach their target, which will cause them to wind up and explode prematurely. Hauling the Sentry after Sentry Busters get close to the Engineer's sentry is recommended, as Sentry Busters cannot move once they begin counting down, but will not protect any other buildings or teammates that may be nearby. An Engineer picking up his Sentry and carry it around the map is not recommended, as it stops the Engineer and his Sentry from attacking the rest of the horde and attending to his other buildings. Knockback can keep a Sentry Buster at bay long enough to destroy it, but once they begin the detonation process, they are immune to it (excluding compression blast). However, regardless of how a team defeats a Sentry Buster, the robot horde will continue to send them out after a mission-specific delay time until the target Sentry is destroyed or the wave is completed. The Rescue Ranger allows Engineers to pick up their Sentry Gun from a distance, assuming that they have at least 100 Metal. This allows them to safely wait until the Sentry Buster starts detonating, then quickly withdraw their Sentry Gun before it detonates.
Sentry Busters will spawn against and target Mini-Sentry Guns, but they will ignore Disposable Sentry Guns, even if it is doing more work than the primary one. If a Sentry is destroyed before the Sentry Buster gets there, it will continue running to where the Sentry used to be and detonate. One Sentry Buster can spawn for each Engineer on the defending team. Should a Sentry Buster be unable to plot a path to its target Sentry Gun, it will simply explode once it enters the playing area.
Destroyed Sentry Busters, whether by themselves or by the players, leave no money. A large cloud of dark grey smoke lasting a few seconds remains after detonation, blocking the view of players within the range of the smoke.
Kill 5 robots in a single explosion from detonating a sentry buster.
||Ctrl + Assault + Delete|
Destroy a sentry buster before it reaches its target.
August 15, 2012 Patch (Mann vs. Machine Update)
- The Sentry Buster was added to the game.
August 17, 2012 Patch
- Fixed Sentry Busters picking disposable buildings as valid targets.
- Fixed an instance of the Sentry Buster sound looping endlessly.
September 16, 2013 Patch
- [Undocumented] Sentry Busters now destroy robots when they explode.
September 18, 2013 Patch
- Notes missed from Monday's update:
- Updated Sentry Busters in Mann vs. Machine mode to damage teammates when they explode.
January 9, 2015 Patch
- Fixed using the Holiday Punch to tickle Mann vs. Machine enemy bots
July 14, 2016 Patch #1
- Fixed sentry buster sounds not being cleaned up properly after detonating
- Only the legs will tint yellow when soaked in Jarate, due to the material proxy required being missing from the material for the pressure mine segment of the model (
- In the Halloween mission Caliginous Caper, Sentry Busters will spawn with Demoman upper arms levitating at their sides, and Spine-Chilling Skull hats on their invisible heads.
- Sometimes, when a Sentry Buster is killed, it will simply vanish instead of crouching and exploding. When this happens, the kill feed will show that the player killed the Sentry Buster with their weapon.
- This can happen when for example, the Sentry Buster has 3 health and the attacker deals 2.5-2.99 damage to the Sentry Buster.
- If this is done with the Cow Mangler 5000 or the Medic's projectile shield, the Sentry Buster will appear as a ragdoll on the ground.
- If the defenders lose the round, and the Sentry Buster is still alive, it will not detonate near Sentry Guns but attack enemies or enemy buildings as if it was not a Sentry Buster but a robot using melee, and will continue to do so until the round resets or the Sentry Gun dies.
- Occasionally in Mannhattan, if the Sentry Buster is active when the robots capture one of the gates, it will rush over toward the capture point and stay there, disregarding the sentry entirely until the robots become active again.
- In this state, it will attack enemy buildings or enemies near it as if it was not a Sentry Buster but a robot using melee, this is because of how giants behave in the map.
- Pyros that airblasts the Sentry Buster into mid-air as it detonates will cause it to use the animation for idling, thus resulting with the Sentry Buster exploding while walking around or idling.
- When a Sentry Buster is shot by something explosive, it will use the voice lines for a Demoman robot exploding his Ullapool Caber.
- If a Sentry Buster is shot while it's in the robot's spawning area, no Ubercharge texture will show up.
- Occasionally, it is possible to see the Sentry Buster's invisible Ullapool Caber floating in the air. This happens due to how Mann vs. Machine works, Robots and Sentry Busters keep "spectating" human players internally until they are ready to spawn, and when a Sentry Buster spawns, the Ullapool Caber gets fixed in the air on the same position of the player they were "spectating" prior to respawning.
- As Sentry Busters can damage robots, they can "defend" the bomb if they destroy a robot that is carrying the bomb.
hitboxes of a Sentry Buster.
- The model of the Sentry Buster references the design of naval contact mines iconic to WWI and WWII naval warfare.
- The Sentry Buster is considered to be a giant Demoman wielding the Ullapool Caber. As a result, it shares animations and hitboxes with the giant Demoman robot (resulting in having invisible arm and head hitboxes) and appears to be holding the Ullapool Caber in first-person view to spectators, with any kills credited to it using the Ullapool Caber kill icon. As voice responses do not appear to be disabled for the Sentry Buster, it will use the giant Demoman robot's voice clips when speaking. Voice commands, such as the "Spy!" one, also refer to the Sentry Buster as a Demoman. Additionally, since it has a head hitbox, it can be headshot for critical damage.
- Since Sentry Busters become immune to damage and explode when their health reaches 1, it functionally has 2499 health as opposed to 2500.
- A Sentry Buster's detonation is linked to its taunt function. This resulted in a now-fixed bug where forcing it to taunt via the Holiday Punch would cause it to explode prematurely.
Promotional art: A group of Sentry Busters chasing an Engineer.
The message that appears if a Sentry Buster destroys a robot carrying the bomb caught in its blast radius.