The first chapter of this book gives some good insights into the
psychological nature of Internet trolls. Psychological
reverse-projection, that sort of thing.
<
https://www.amazon.com/Falling-Into-Fire-Psychiatrists-Encounters/dp/0143125710>
The chapter is actually about a chronic repeat patient to the
psychiatric unit who repeatedly swallows foreign objects when under
stress, like spark plugs, barbecue skewers, shower curtain rings, etc.
The frightening thing is that apparently in the psychiatric
classification literature, repeatedly swallowing large sharp objects is
categorized a "moderate" level of persistent self-injury behavior..