Hypno was definitely one of the scariest Gen 1 pokemon.
While it awaits its prey, it polishes its pendulum. If anyone comes by, Hypno will hypnotize them and eat their dreams. It carries away people having good dreams and is even known to have stolen a child at one point.
Don’t forget the psychic ones. Any world with abundant telepathy and mind control is pretty much guaranteed to be a dystopia.
Hypno was definitely one of the scariest Gen 1 pokemon.