Image of Mother Brain from a Metroid: Zero Mission cut scene. Mother Brain is the biological computer of the Space Pirates and one of the main antagonists in the Metroid video game series. She usually appears as the final boss. Mother Brain is, in essence, a huge one-eyed brain in a jar. Her attacks consist of the automated defense systems surrounding her, though the eye may join in once the jar is ruptured.
There is debate on whether or not she is the true leader of the Space Pirates. According to Super Metroid's manual, Metroid: Zero Mission, Zero Missions' manual, and both official mangas, Ridley is the leader of the Space Pirates while Mother Brain is just a biological computer which controls Zebes' defenses. However, the instruction manual for the original Metroid game, the in-game introduction in Super Metroid, and the Nintendo Power comic refer to Mother Brain as the leader of the Space Pirates, with the original Metroid instruction manual going so far as to say that Ridley is actually controlled by Mother Brain. Metroid Prime confuses the issue even further in the Pirate Data logs by alluding to a Security Command that issues orders, including the reconstruction of Ridley himself.
Some argue that the original intention was much more simplistic and obvious than is currently made out to be. Mother Brain was the final boss of the game, both the stated and implied leader, while Kraid and Ridley were mere subordinate mini-bosses. Subsequent games and mangas have only altered this after new people took over the series following the death of creator Gunpei Yokoi. Others point out that translation errors are responsible for many of the incorrect information in the Metroid I manual (including referring to Samus Aran as male and a cyborg) so it should not be used to support any kind of canon and that Zero Mission and other games since then have only corrected the original mistakes. They also point out that Ridley was referred to as the leader of the pirates in Super Metroid, well within the lifetime and creative control of Yokoi.
Whatever the original intention might have been, Nintendo has made it quite clear that Mother Brain is not the leader of the Space Pirates now, but it seems the arguments continue across the internet and between diehard fans regardless.
Games
 Mother Brain's second form from Super Metroid. In the NES edition of Metroid, Mother Brain is defended by Zeebetites, life support units that block Samus' path.
Mother Brain is defeated by first breaking her tank with missiles, and then pummeling the brain itself. In Super Metroid, she has an ace up her sleeve: after the destruction of Mother Brain's tank, she is revealed as part of a large, powerful monster and must be defeated in her new, larger form.
She is notorious for her use of a villain cliché: Her seeming death initiates a self-destruct device, giving the player only a few minutes to escape before the area/atmosphere/planet is incinerated. Catastrophic self destruction countdowns are also a well-known unofficial trademark of the Metroid series (most of the Metroid games feature at least one).
Cameo Appearances
CNMotherBrain.jpg
The Captain N version of Mother Brain.
In her appearance as a supervillain in the TV show Captain N: The Game Master, she had gained a snooty female "face". She also had this appearance in an obscure German comic, with even larger and more groutesque lips.
| 
