mother brain
The main antagonist and final boss of Metroid, it's remake and Super Metroid. A once benevolent Chozo supercomputer that ascended into being the leader of the Space Pirates due to her ability to propagate and weaponize Metroids.
She is an artificial brain with spikes jutting out and has a single eyeball. She is protected in a massive glass container that is connected with wires and cables. In Super Metroid she even gains a fully mechanical body that has a mouth, torso, arms and legs.