Shapeshifters who can look like anybody, evil twins who steal your identity... I think that’s my nightmare class of pop story plots. Something really freaks me out about them.
Are you talking the episode with the evil shapeshifter, the virtual realty clone, the mental construct clone, the alternate timeline clone, the mirror universe clone, the other mirror universe clone, the biological clone, or the clone that's an ambiguous mix of a few of these?
DC comics can't get enough of it, and the Arrowverse leans into all the comic book insanity. We even get Oliver Queen's boxing glove arrow at one point.