The Alien Heart was the last boss in the first Contra game and its remake (except the MSX2 port where it appears as a minor boss). It is literally an alien heart that nurtures the cocoons containing the yet-to-be awake aliens. It is theoretically an alien life form that is responsible for spawning the newborn aliens. In nearly all of its incarnation the "alien heart" also seems to have a decent self defense mechanism (mostly projectile or energy based weapon). Combined with the streams of newborn aliens, it is proved to be a difficult challenge. Once the "alien heart" life-form is out of commission the alien's major operation is halted to a full stop due to the sudden drop of alien workforce. In the Famicom version of Contra, the entire Alien Lair pulsates as though alive. One could infer that the entire level is one living creature and the Alien Heart is an organ in it.