Clone and copy-paste consciousness and continuously cultivate gu worms to screen for new personality hosts.
At present, humans cannot achieve consciousness transfer because the quantum storms in the human brain are too complex, but it does not mean that the Compound-Eyed Observers cannot do it.
Perhaps the Observer's thoughts are relatively simple?
Besides, Harrison Clark said it was "potentially immortal" rather than definitely immortal.
That's because cloning and copy-pasting consciousness may also have limitations in the number of times it can be done.
When the number of times exceeds a certain threshold, even if the body is still alive, the thought may tend towards collapse and gradually twist into another personality.
Or the consciousness would directly collapse, leading to a physiological living but psychologically dead state.
For example, are the current million Compound-Eyed Observers the same individuals as the million Compound-Eyed Observers a million years ago?
