Monsters from the Id.
J.J. Adams: What is the Id?
Morbius: It's an obsolete term. Once used to describe the elementary basis of the subconscious mind.
J.J. Adams: Monsters from the Id. Monsters from the subconscious.
The big machine - cubic miles of Klystron relays - enough power for a whole population of creative geniuses operated by remote control. Operated by the electromagnetic impulses of individual Krell brains.
Morbius: To what purpose?
J.J. Adams: In return, that machine would instantaneously project solid matter to any point on the planet, in any shape or color they might imagine ... for any purpose! Creation by mere thought.
Morbius: Why haven't I seen this all along?
J.J. Adams: Like you, the Krell forgot one deadly danger ... their own subconscious hate and lust for destruction. The beast. The mindless primitive.
Even the Krell must have evolved from that beginning. And so those mindless beasts of the subconscious had access to a machine that could never be shut down. The secret devil of every soul on the planet all set free at once to loot and maim and take revenge and kill!
Morbius: My poor Krell! After a million years of shining sanity they could hardly have understood what power was destroying them.
Yes, all very convincing but for one obvious fallacy - the last Krell died centuries ago But today, as we all know, there is still at large on this planet a living monster.
J.J. Adams: Your mind refuses to face a conclusion.
Morbius: What do you mean?
J.J. Adams: You still refuse to face the truth.
Morbius: What truth?
J.J. Adams: Morbius, that thing out there - it's you.
Morbius: You're insane!
J.J. Adams: We're all part monsters in our subconscious! So we have laws and religion.
Morbius: Let me go!
J.J. Adams: Here's where your mind was artificially enlarged. Consciously it still lacked the power to operate the great machine but your subconscious had been made strong enough!
Morbius: I won't hear you!
J.J. Adams: You've got to listen! Twenty years ago, when your comrades voted to return to Earth you sent your secret Id out to murder them! Not quite realizing it, of course, except maybe in your dreams.
Morbius: What man can remember his own dreams?
J.J. Adams: At least when we approached from space, you remembered enough to warn us off. But when you thought we were a threat to your little egomaniac empire your subconscious sent its Id monster out again! More deaths, Morbius. More murder!
Morbius: And now this too? Harm my own daughter?
J.J. Adams: But now she's defying you, Morbius - and even in you, the loving father, there still exists the mindless primitive ... more enraged and more inflamed with each new frustration. So now you're whistling up your monster again to punish her for her disloyalty and disobedience! And if you don't do something about it soon it's going to be coming right through that door.
Morbius: My evil self is at that door, and I have no power to stop it!
Dialogue leading to the climax of the film Forbidden Planet.
Image is of the Id monster from the film.