It’s from a 1970s piece of Star Trek fan fiction.
It was a tongue in cheek piss take about a character called Mary Sue who all the other characters immediately fell in love with, and who solved all their problems and saved the day.
Now it’s a term for any character too powerful and clever to be true.
It can work with villains because you want them to be tough to give the hero a challenge, but Hannibal Lector is a step too far.
He was alright in the films, but the TV series with Mads Mikkelsen was something else. He was one of the central characters and was just too good to be true, he is a psychiatrist, surgeon, musician, artist, gourmet cook, the list goes on and on.