If you're not super tuned into what kids these days are into, chances are you've never heard of Bendy and the Ink Machine. Basically, it's the new Five Nights at Freddy's. Bendy in Nightmare Run is a cartoony horror game that's perfect for all sorts of reaction videos and other similar things- Much like FNAF. Bendy has a massive amount of merch, making it the most popular thing I've never heard of (at least until this demo):

Bendy in Nightmare Run brings Bendy to mobile in this level-based boss battling runner. It's a real cool game by itself, and I'm super excited to give the "real" Bendy game a try on Steam when I get home so I can see what all the fuss is about!