Mother Brain

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Mother Brain 1
Location Mother Brain Room, Tourian
Health 3000

Mother Brain is the final boss of the game. She has three phases, which are usually referred to as MB1, MB2, and MB3.

MB1 rests within her glass tank. MB2 rises from the ground into a mechanized body, fought before acquiring Hyper Beam. MB3 is an ultra-aggressive version of the previous form, fought after acquiring Hyper Beam and/or during Standup Glitch.


General Knowledge

Mother Brain and the glass are only vulnerable to Missiles and Super Missiles.

Mother Brain has 3000 health. Shots that strike the glass do not deplete her health and only damage the glass, while shots that strike her damage both.

Partially breaking the glass to begin damaging her requires 6 shots while fully breaking the glass requires an additional 12 shots.

Mother Brain will not transition from her first phase into her second phase until both the glass tank surrounding her has been completely removed and her health has been fully depleted.

Contact with Mother Brain deals 30 / 60 / 120 damage to Gravity Suit / Varia Suit / Power Suit Samus, respectively, and ignores invulnerability.

Contact with the surface above or in front of Mother Brain's glass tank deals 15 / 30 / 60 damage to Gravity Suit / Varia Suit / Power Suit Samus, respectively.


If Samus is struck by a turret shot, it will produce a cloud that lingers in the air for around a second. This cloud can consume a Missile or Super Missile if one comes in contact with it, which is more reason to be careful when firing at MB1 in lower-percentage categories. There is a group of white pixels that will appear in the air as long as this cloud is present.

Although MB1's glass tank can be accessed and struck from the back through glitched means, it is not possible to break MB1's glass tank from the back. It will show that it has begun to crack, but never break open.

Rinkas being present while you damage MB1 can cause substantial lag, so it is recommended that you destroy them. Freezing them before destroying them will greatly increase the time it will take for them to respawn.

In categories such as 14% Speed where the above is not possible, it is instead recommended that you simply dodge them to the best of your ability. Jumping then morphing to dodge Rinkas while in midair is probably the most effective way to dodge all of them at once.

Below are some examples of how to handle MB1 in categories where Ice Beam is not present.


After MB1 has been defeated, the screen will scroll directly onto Mother Brain so she can begin transitioning into her second phase. Although you can minimize the time the game spends scrolling the screen by being closer to Mother Brain right when the scrolling occurs, doing so does not save time as Mother Brain will always take approximately the same amount of time to transition regardless of the time spent scrolling the screen.

Categories that have an abundance of energy, such as 100%, can defeat MB1 in the manner below, which will reduce the travel time of Super Missiles, the lag during the sequence, and the likelihood of interference from turrets and Rinkas.

Mother Brain 2 / 3
Location Mother Brain Room, Tourian
Health 18000 / 36000


General Knowledge

Any part of Mother Brain's body will deal 30 / 60 / 120 damage to Gravity Suit / Varia Suit / Power Suit Samus, respectively, and ignores invulnerability.

Mother Brain's eye laser will deal 30 / 60 / 120 damage to Gravity Suit / Varia Suit / Power Suit Samus, respectively.

Mother Brain's rings will deal 20 / 40 / 80 damage to Gravity Suit / Varia Suit / Power Suit Samus, respectively, and ignore invulnerability.

Mother Brain's bombs will deal 40 / 80 / 160 damage to Gravity Suit / Varia Suit / Power Suit Samus, respectively.

The explosion from Mother Brain's bombs will deal 20 / 40 / 80 damage to Gravity Suit / Varia Suit / Power Suit Samus, respectively, and can strike multiple times depending on how Samus comes into contact with it.

The center of the explosion from Mother Brain's bombs will deal 0 / 1 / 3 damage to Gravity Suit / Varia Suit / Power Suit Samus, respectively.

When below 4500 health, Mother Brain will gain the ability to use her explosive red beam attack, which will deal 100 / 200 / 400 damage to Gravity Suit / Varia Suit / Power Suit Samus, respectively, and can strike multiple times depending on how Samus comes into contact with it.

When at zero health, Mother Brain will gain the ability to use her rainbow beam attack, which she will being charging as soon as possible, and will deal 300 / 600 damage to Samus with Varia Suit equipped / Samus without Varia Suit equipped, respectively. This will also drain Samus' ammo, draining 1 Power Bomb each frame, and 1 Missile and 1 Super Missile every 3 or 4 frames. This drains 75 Missiles, and in the vanilla game will drain all Super Missiles and Power Bombs.

Offense / Defense

As MB2's body ignores invulnerability, it serves as a fantastic way to deal damage to yourself.

MB2's bombs can be destroyed by your own bombs. As a safety option, it is not recommended because of the time required to destroy her bombs. MB2 has a tendency to immediately spawn a bomb after one has been destroyed.

Both the bomb object and the bomb explosion can be negated by the effects of either Screw Attack or pseudo-Screw, but this is rarely relevant.

MB2 cannot create another bomb when one is already on screen and she will sometimes crouch before planting bombs. MB2's frequency in spawning bombs will increase the more you stay grounded.

MB2's eye laser can also be negated by a "screw" effect. It is MB2's secondary counter to aerial actions, as it travels in a straight line directly out of her eye.

Because MB2's rings ignore invulnerability and fire in a volley, it is quite easy to be "combo'd" by them if you aren't careful. This is one of MB2's most fearsome attacks since it is available to MB2 during the entire fight, cannot be negated by a "screw" effect, and cannot always be predicted. MB2 tends to fire rings based on how often you leave the ground.

Despite MB2's body and her rings ignoring invulnerability, they do happen to grant a normal invulnerability period.

MB2's redbeam is composed of a number of explosion hitboxes making it possible for multiple to strike Samus at the same time. It is also possible for redbeam to not deal any damage to Samus when it appears to land. This is more commonly experienced when morphed, but it is entirely possible to have happen even when Samus is standing still. It simply depends on what pattern is formed by the explosions of the beam.

If MB2 produces a bomb, MB2 will not be able to fire a redbeam until that bomb detonates.

Perhaps surprisingly, redbeam can also be avoided by "screw" effects. It will also sometimes not be generated depending on which sprites are on screen at the time of MB2 attempting to fire it, indicated by MB2's hand flicking without creating a beam.

"Screw" effects as a safety option are inherently slow because they require you to stop charging the beam, increasing the length of the fight.

Players who are experienced enough to consistently survive MB2 in lower-percentage categories tend to agree that the scariest part of the fight is around the moment that MB2 gains the ability to fire redbeam. To prevent being caught off-guard, it is important to keep track of how many charged shots have struck MB2 during the fight to know when she will be able to fire it. Once you have avoided this initial redbeam, the rest of the fight should be much easier to handle than before.

A common piece of misinformation is that MB2 gains the ability to fire redbeam at 25% health when she actually gains it when she goes below 25% health, similar to how Ridley actually enrages when he goes below 50% health, not at 50% health.

MB2's rainbow beam is unavoidable if it fires. Even if Samus is out of bounds when it is fired, it will drag Samus back inside the chamber, dealing damage and stunning her.

The energy drain from MB2's rainbow beam will take up to 15 frames longer to occur depending on how far away Samus is from the right wall when it makes contact with her.

MB2 will move forward frequently during the fight, and will move backward when her brain is struck. Even uncharged beam shots and normal bombs can force her back as long as they strike her brain.



Below are video examples of four MB2 fighting styles using 14% Ice items.


Underneath (Jumping)


Wall (Jumping)


Each fighting style has its own positives and negatives that you should weigh appropriately when deciding which to use. Although the video examples give a decent indication of the strengths and weaknesses of the styles, they do not showcase every possible detail, and are not indicative of how you in particular would execute them.

A negative of fighting underneath MB2 is that it suffers from needing to perform turnaround animations during the fight in response to MB2 moving forward and backward during the fight. Every time a turnaround animation is performed, it prevents the beam from charging for six frames until the turnaround animation completes. Although it is a minor drawback, it can add up over the course of a 4-7 minute fight.

Another negative of fighting underneath is that shots can be blocked by her hand.

Fighting underneath MB2 without performing jump manipulation can result in more opportunities to be sniped by one of MB2's other attacks when you attempt to avoid a bomb explosion.

Fighting underneath MB2 while performing jump manipulation can result in opportunities to accidentally bump heads with MB2 when she ducks down to drop a bomb.

Although fighting against the wall removes most issues that fighting underneath has, the primary negative of fighting against the wall is shots can miss due to MB2 ducking her head. Additionally, a lack of jump manipulation may cause more hard-to-dodge patterns to occur in comparison.

Jumping frequently during the fight will encourage MB2 to use something other than her bombs because she is programmed to counter aerial movement with her other two attacks. This will make the ground a safer place during the fight for avoiding those attacks, and should cause you to need less turnarounds during the fight. With frequent enough jumps, you can essentially keep MB2 locked into those two attacks.

Styles that involve frequent jumping may quickly cause the player to experience fatigue in their hands depending on how they grip their controller.

The "Wall (Jumping)" style may take the longest to become comfortable using if you choose to use it, as your understanding of MB2's AI will greatly impact how effective it is.

When fighting against the wall, it is helpful to be in the habit of crouching before jumping over bombs as crouch jumping will provide additional height, which can make avoiding certain volleys less tense. There are some situations where without the extra height, you may have to land on top of a bomb explosion that hasn't been cleared from the ground yet, and hope that your positioning was on point to nullify its damage.

Fighting against the wall may be the worse option for safety depending on your level of experience and execution.

During periods of time where MB2 has her head sticking out and appears to be locked into place for a few seconds, the recommended course of action is to either not jump at all, or stop jumping and then resume jumping right before you think this phase will end. If you do not jump at all, she will more than likely, once this phase ends, drop a bomb followed by an immediate ring volley.

It is of the utmost importance that you keep track of how many shots you have landed during the fight to know when MB2 will gain the ability to redbeam. If you happen to lose count, there are a few contingency plans. You can possibly abuse the fact that MB2 will preemptively cock her head back to fire redbeam when a bomb is down, which will act as a visual cue for when the first redbeam will be incoming. Alternatively, you may be able to extrapolate the time in which MB2 should be around redbeam phase based on the time in which, for example, MB1 hit the ground after her defeat, or MB2 rose from the ground. The former would require a timer and having knowledge of what amount of time typically passes between those two points. For example, if you are having a solid 14% Ice fight in terms of speed, MB2 should gain the ability to redbeam a little over three minutes past the point when MB1 hit the ground.

Ultimately, what matters the most is that you are able to defeat MB2. Even if a style seems like it would save slightly more time than another, the time you would potentially save means nothing if you cannot actually survive the fight.


You should be able to consistently fire three shots at MB2 every redbeam cycle. You should be able to squeeze in a 4th at least half of the time; however, depending on the sequence of events (how quickly MB2 is firing redbeams, how efficient are your shots, et cetera), it may be difficult to both release the fourth shot at the right time and input a jump to dodge an incoming redbeam. There are some ways to deal with this - three of which are listed below in the order of safest to riskiest.

It gives you plenty of space on the right side of the room with which to dodge anything MB2 could possibly throw at you. If all she does is fire a redbeam, then you simply run back to the wall, fire three shots, run back to her, and repeat the process ad nauseam.

This strategy probably causes an average loss of over a second per redbeam cycle, but should make the redbeam phase a cakewalk.

By holding your third charge shot on a cycle, you can fire it around the time MB2 would fire her redbeam so you can focus more of your attention on avoidance. It usually causes a little bit of lag by firing it around the time of a redbeam, which actually helps give you more time to react to MB2. It costs very little time, especially if you only do it on certain redbeam cycles. For example, a visual cue you can use to gauge whether or not you should hold your shot is how much of MB2's redbeam is left on the screen when you fire your first shot of a cycle.

Similar to the above, except you do not hold your third charge shot, and instead hold your fourth charge shot at times where you need to jump while charging it. You basically predict that MB2 will immediately fire a redbeam after third shots and jump at the appropriate time, continuing your charge while in the air and firing it at the appropriate time.

14% Ice

Charged Ice deals 90 damage, meaning it will take 200 shots to reduce MB2's health to zero.

MB2 will gain the ability to redbeam after 151 shots land.

Ice Shield particles also deal 90 damage each, so they are equivalent to a charged Ice shot.

The best way to open the fight is with three Ice Shields. You will want to position yourself next to the brain before it rises up from the ground, and charge the beam for the first Ice Shield the moment MB2's foot first appears as it emerges from the ground. Once the beam has reached its maximum visible charge (size), jump and hold jump so that all Ice Shield particles will connect with MB2. Do the same for the second. For the third, you will want to move forward a bit as you fall down since MB2 will more than likely start backing up. Although unlikely, it is possible that MB2 will instead not move backward and react with an eye laser or ring volley, so keep that in mind. If you want to be safe, only perform two Ice Shields instead.

You may find it to not be worthwhile to perform Ice Shields during later parts of the fight, such as during redbeam phase, as it can be very difficult to make all four particles consistently land. Even if you were able to, it would take you out of position and may affect your rhythm of charging the beam. It may be possible to squeeze the extra Ice Shields in during the middle of the fight, but would be quite risky due to MB2 being able to react with moving forward or using an aerial counter. There is also the chance that a particle does not get consumed, which would prevent the beam from being used.

14% Speed

Charge by itself deals 60 damage, meaning it will take 300 shots to reduce MB2's health to zero.

MB2 will gain the ability to redbeam after 226 shots land.

Not much to explain here. It's basically just a more strenuous 14% Ice fight, so enjoy.


Charged Ice + Wave + Plasma deals 900 damage, meaning it will only take 20 shots to reduce MB2's health to zero.

MB2 will gain the ability to redbeam after 16 shots land.

There isn't much that needs to be explained here. The fight is halfway over by the time MB2 does anything, and you usually only have to avoid one redbeam to survive that phase, so unless your familiarity with the fight is lacking, MB2 here is barely a threat.

The above information can also apply to 100% Items, 100% Map, GT Classic, and Reverse Boss Order.


Charged Ice + Wave + Spazer deals 300 damage, meaning it will take 60 shots to reduce MB2's health to zero.

MB2 will gain the ability to redbeam after 46 shots land.

Although this version of the fight is substantially longer than the above, certain 14% strategies should not be involved. Namely, fighting underneath MB2 is not advisable due to Spazer's width; however, if you want to still perform jump manipulation, you can freely abuse medium-sized jumps with Hi-Jump Boots during the fight.

A way to potentially save time during MB2 that applies more to Any% PRKD than other categories involves MB2's rainbow cutscene. MB2 will not transition into her rainbow cutscene until a) her health becomes zero and b) she is off of her attack cooldown. Basically, depending on MB2's attack sequence, she can either transition into her rainbow cutscene the moment she hits zero health, or she may spend some seconds on attack cooldown from a redbeam, which wastes time. MB2's redbeam causes an attack cooldown of close to four seconds (meaning she cannot do anything for that amount of time), which affects her transition. It may be possible (perhaps through efficient charge beam usage, or perhaps through jump manipulation or a similar sort of manipulation) to somewhat consistently have the 60th shot land around the time she is off attack cooldown rather than around the time she fires another redbeam, so that you can minimize the amount of time MB2's delay costs you.

As you may notice from the video examples, when you are aware that MB2 is close to zero health and believe she will not have time to fire another redbeam, you can reduce the distance between Samus and MB2 when firing the remaining shots. You can do this to potentially prevent another redbeam from occurring, which as explained previously, would place MB2 on attack cooldown and delay the rainbow cutscene further.

Examples of MB2 fights where MB2 immediately transitions into her rainbow cutscene include Saturn's GT Classic TAS and Saturn's Reverse Boss Order TAS. You can witness that the moment that the 20th shot connects, MB2 transitions without delay. Behemoth's 43:46 includes a genuine example of this concept, with the 60th shot landing while MB2 is off attack cooldown after recently planting a bomb, resulting in a transition that isn't delayed.

Rainbow Cutscene

Before transitioning into her third phase, Mother Brain will, of course, unleash her rainbow beam upon Samus, and then will be attacked by the Super Metroid before she is able to fire another.

If you are above a certain threshold after the first rainbow beam, Mother Brain will fire shots at you until you're below that line, possibly including additional rainbow beams.

Suit Threshold
Gravity 100
Varia 180
Power 340

Note that you can be at the threshold without needing to take further damage, so for GT Classic, getting hit by the rainbow beam at 700 health for Standup Glitch with Varia unequipped will leave you at 100, and there's no need to damage down from there.

It's possible, though rare, for Mother Brain to kill Samus during these additional damage-down shots under certain conditions. The most common death scenario is when Mother Brain drops a bomb when Samus is between 101 and 120 health, then shoots a volley of two rings. The bomb hits for 40, then the rings hit for 20 each, then the bomb can double-hit with its explosion for 20 each.

Interestingly, the speed of the cutscene - specifically, the length of time it takes for Mother Brain to crouch down during the Super Metroid's attack - is variable.

For categories where the player is unable to perform the Standup Glitch, the primary factor that will determine how quickly Mother Brain will crouch down is actually her foot placement. If Mother Brain's foot is placed a few pixels more forward compared to what is normal, this will cause her to spend less time being attacked by the Super Metroid before crouching down, thus resulting in a swifter cutscene.

Sniq foot.png Sat foot.png

The left image is Mother Brain's normal foot placement. The right image is Mother Brain's "more forward" foot placement.

The reason why the resulting swifter cutscene happens is related to Mother Brain's head. How it shifts during the cutscene directly determines how long the cutscene takes.

The "more forward" foot position was theorized to occur when Mother Brain steps slowly backward before firing redbeam. Observations made in April 2022 by ShinyZeni and ProfessorSchool suggested that Mother Brain's behavior could be manipulated to force the "more forward" foot position. The required manipulation is performed during Mother Brain's second phase when her health is reduced below 25% and the redbeam ability is gained. For the manipulation to work, the damage that puts Mother Brain below 25% must occur as she is stepping forward. After taking this damage, she will step backwards. If the manipulation worked three things will occur:

1) Mother Brain will step backwards and her foot will be in the "more forward" placement.
2) The length of the backwards step will be abbreviated from a normal 13 frames to 3 frames, making it easy to notice.
3) Mother Brain will sit down approximately 3 seconds earlier in the ensuing cutscene than if no manipulation was performed.

The manipulation is demonstrated in the video below.

Below is a comparison of various tool assisted speedruns to demonstrate the potential difference in time Mother Brain takes to crouch during the cutscene.

In terms of cutscene speed, Cpadolf's 100% is 2.5 seconds faster than Saturn's GT Classic, 3.45 seconds faster than Saturn's Any%, and 5.53 seconds faster than Sniq's Any%, meaning that Saturn's GT Classic is 0.95 seconds faster than Saturn's Any% and 2.97 seconds faster than Sniq's Any%, and Saturn's Any% is 2.08 seconds faster than Sniq's Any%. (figures are approximations)

The reason why Cpadolf's 100%, in particular, is so much faster than the others is because Samus is able to influence Mother Brain's head movement, independent of her prior foot placement. Saturn's GT Classic would have been able to do the same, but did not influence her as effectively, as perhaps it was not known at the time that it was possible to do so.

Being airborne, for example using Space Jump, then landing at different times while the Baby is draining Mother Brain's energy, will impact the length of time it takes for Mother Brain to crouch during the cutscene. Specifically, being airborne before Mother Brain turns blue, and landing shortly after blue Mother Brain begins walking forward appears optimal. Landing later or staying on the ground throughout Mother Brain's transition to blue each result in an extra 1-3 seconds before Mother Brain crouches. This was tested empirically and is demonstrated in the video below.


General Knowledge

Mother Brain has 36000 health.

Any part of Mother Brain's body will deal 30 / 60 / 120 damage to Gravity Suit / Varia Suit / Power Suit Samus, respectively, and ignores invulnerability.

Mother Brain's rings will deal 20 / 40 / 80 damage to Gravity Suit / Varia Suit / Power Suit Samus, respectively, and ignore invulnerability.

Mother Brain's bombs will deal 40 / 80 / 160 damage to Gravity Suit / Varia Suit / Power Suit Samus, respectively.

The explosion from Mother Brain's bombs will deal 20 / 40 / 80 damage to Gravity Suit / Varia Suit / Power Suit Samus, respectively, and can strike multiple times depending on how Samus comes into contact with it.

The center of the explosion from Mother Brain's bombs will deal 0 / 1 / 3 damage to Gravity Suit / Varia Suit / Power Suit Samus, respectively.


MB3 can only unleash rings and bombs, but will attempt to unleash them at a rate of roughly one attack per second, and will step forward while attacking with them much more than before.

MB3 can have multiple bombs active at once; however, their explosions will not expand nearly as far as MB2's.

Hyper Beam deals 1000 damage; therefore, 36 strikes will destroy her. Hyper Beam will also temporarily stun MB3 when it connects, pushing her back and preventing her from using attacks during this period. It is possible to keep MB3 stunlocked during the entire fight by landing shots frequently enough.

Having multiple Hyper Beams on the screen at once will generate substantial lag, so if you're optimizing for real time, try to minimize the distance between Samus and MB3 while firing so that this is avoided.

In categories that do not obtain Hi-Jump Boots, MB3 can be handled quite easily in the manner shown below. For most of the fight, you should be able to stand aligned with the closest dark vertical pipe / fifth floor tile from the right wall, hold angle up, press and hold jump, then press and hold shot about ten frames later until four Hyper Beams have been fired, and repeat this process until you are victorious. You may have to make slight adjustments depending on how MB3 shifts around, or if MB3 is able to spawn a bomb or rings.

Often referred to as the "lag corner", a beginner's strategy for this phase is to stand in the corner of the right wall, face MB3, and hold the shot button and angle up during the entire fight. Even though it is very slow, it requires very little effort to survive the fight.

See also