Идиома: red herring (дословный перевод: красная селёдка %))
Значение: A clue that leads in the wrong direction.
Фраза, или информация, призванная отвлечь от темы. Отвлекающий манёвр.
Something deliberately misleading to divert your attention from the main subject
Вики об этой идиоме: https://en.wikipedia.org/wiki/Red_herring
Происхождение: a piece of information or suggestion introduced to draw attention away from the real facts of a situation. (A red herring is a type of strong-smelling smoked fish that was once drawn across the trail of a scent to mislead hunting dogs and put them off the scent.)
Пример: I felt this was a red herring.
The mystery novel has a couple of red herrings that keep readers off guard.
The detectives were following a red herring, but they're on the right track now.