The Observers are an alien race who claim they are hyperintelligent, psychic, and all confusingly share the name "Observer". The race also claims to be without bodies (despite obvious evidence to the contrary) and carry their bright-blue brains in large Petri Dishes, rather than inside their (supposedly nonexistent) skulls.
They all claim, to be omniscient and omnipotent, much like Q from Star Trek and his people, but they frequently fail to demonstrate these supposed abilities. In one of their earlier appearances, the one that later came to be known as Brain Guy by the other Mads, had tested the rest of the cast to see if any of them are deserving of the right to become part of their kind. He was surprised when Tom Servo scored higher than even him, which lead to his being painfully punished.
In time the survivors were able to reconstitute their planet (in Experiment 904 The Deadly Bees).