What is a video that you did not expect to take such a s udden and very dark turn?

Lasagna Cat.

Salad Fingers.

Too many cooks.

For me, easily Spec Ops: The Line.

That game took an incredibly dark turn during the White Phosphorus scene. You know those top-down camera views in Call of Duty where you shoot enemies from the sky? This game does that, too. And then, boom, you find out that you just burned a refugee camp to the ground with phosphorus bombs. And this game actually forces you to walk through the travesty you just caused, and see all of the flaiming remains of soldiers screaming for help and buildings and cars burning and on fire. But, the most haunting part of that scene is the burning carcass of a woman holding her child as the white phosphorus breaches through the gate.

That image has been burned into my brain. 10/10 will not be playing again anytime soon

Wait, so you're asking about video GAMES? You somehow failed at asking that in the title, you asked for videos.
- Yeah I was confused too. I clicked to see if people were talking about films, short form videos, or what. I didn’t expect games.
I’m a bit surprised by this. Had you not heard anything about the game? I’m not saying I expected that but I thought it was pretty clear from the start that the game was going to be subversive
- Depends on when you played it. It came out in a decade of generic war shooters (including other spec ops games) so the subversion slid under most people's radar, which was intended. There are subtle hints as you play, but iirc the scene described above was the first time the game really slaps you across the face.
  
  It took a few years for the game to gain a cult following and recognize it for what it is. Nowadays the only people who go back to play it already have some idea of what they're getting into.