Can someone explain the hitchhiker phenomenon? Preferably with examples

I see people often refer to “the hitchhiker effect” but rarely explain beyond the naming phrase. Most recently was the Encounters docuseries on Netflix where the Navy guy claimed to be experiencing something similar and it all but amounted to an average case of sleep paralysis.

Is there any more information on the hitchhiker effect with the phenomenon? Google doesn’t seem to turn anything up and I don’t want to read a book to understand a single concept