| Sentry Buster
| Basic Information
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. Upon reaching its target, it crouches and begins beeping. A few 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 robots around it.
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 target Sentry out of the detonation zone will save it, as Sentry Busters cannot move once they begin counting down, but will not protect any other buildings that may be nearby. Should the Engineer be daring, he can pick up his Sentry and carry it around the map, which will cause the Sentry Buster to chase him indefinitely until it gets close enough to explode; this does, however, stop the Engineer and their Sentry from attacking the rest of the horde. 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. 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. As a result, it may be preferable to allow it to do its work and simply build a new Sentry Gun.
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.
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.
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.
- Defenders will occasionally announce its presence as a giant robot instead of as a Sentry Buster.
- 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 (demo_buster.vmt).
- 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.
- If the Defenders lose the round, and a Sentry Buster reaches a Sentry Gun, it will attack it as if it were wielding a broken Ullapool Caber, and will continue to do so until the round resets or the Sentry Gun dies.
- In some occasions, a Pyro that airblasts the Sentry Buster as it loses its health or reaches its target will not animate its detonation or its associated sound, thus resulting with the Sentry Buster exploding without warning, usually in midair.
- If a Medic uses the projectile shield to kill a sentry buster, it will not explode but instead become a ragdoll.
- Sometimes, when a Sentry Buster explodes, you can hear a human Demoman taking damage, even if there is no Demoman in your team. Even if there is one, it still occurs whether or not he has recently taken damage.
- 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.
- Sentry Busters will sometimes say "Ka-boom!" or "Ka-blooie!" randomly, even though those are voice lines that are only triggered when a Demoman (human or robot) destroys a building.
hitboxes of a Sentry Buster.
- 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. Additionally, since it has a head hitbox, it can be headshot for critical damage.
A group of Sentry Busters chasing an Engineer.