A cliché in popular fiction that was common at one point in time, but has become so overused that it no longer has any relevance, so whenever it's used consecutively, it is as though the writers are "beating up a dead horse".
Mick: You know what I hate? That new music video by Chris Brown. It's basically a Michael Jackson rip-off with triads.
Fred: Triads? That's been a dead horse cliché since the last decade.
Mick: Yeah, they're just beating up a dead horse.
Fred: Triads? That's been a dead horse cliché since the last decade.
Mick: Yeah, they're just beating up a dead horse.
by TheWriter May 19, 2013