How to become a philosophical zombie? I was wondering if the following mental state was possible and if so, if it was documented.

The concept would be not to be conscious for a while, to be in some way in automatic mode. And because of any stimulus, return to a normal state with all the recent memories in mind but the impression that they all happened in a second.

The goal is clearly not to have to wait for a given event or to put an unpleasant period of time behind you.
A true philosophical zombie would form the same memories of being conscious that a conscious human would. By definition, a p-zombie is atom-for-atom identical to a real person, and would be impossible to distinguish by any means, even through the memories stored in the zombie's brain! If consciousness was one day imbued into a 30-year-old philosophical zombie, they would not realize that they had previously not been conscious.

As a corollary, science could never know if it had successfully produced a p-zombie, because if you gave someone the zombie pill, nothing measurable would change and after it wore off they would not know anything happened. It would be indistinguishable from a placebo.