It is what happens when you watch an embedded YouTube video on another site and then watch a couple dozen related videos that are displayed after the previous video completes. The rabbit hole effect is only encountered after at least an hour has passed and you regain your sense of temporal awareness. This effect usually is followed by, "How the fuck did i get to this video?"
"Dude, I was watching the Macho Claw mod video and an hour later, I realized that I'd watched at least 10 videos about My Little Ponys without remembering how I got there. The YouTube Rabbit Hole is a dangerous thing."
by BlindBastard April 17, 2016