Noun: A video game, most often a PC game, that's popular only because YouTubers are currently playing it. Regardless of whether they're actually good or not, they're simply fads that will come and go over the course of 12 months, maximum. Prime examples of let's play trash would be Slender: The Eight Pages, Minecraft, Five Nights at Freddy's, Happy Wheels, Undertale, and Bendy and the Ink Machine.