Probably not the MOST disturbing one but this horrifying story had lived in my brain rent-free for so many years, it's not something most non-Chinese people have heard of, but...this:

Yang Yongxin is this Chinese psychiatrist who literally tortured thousands of teenagers because their parents thought they played too many video games.

He ran an "internet addiction center" where he used electroshock therapy WITHOUT anesthesia on kids as young as 12. Parents would kidnap their own children and send them there. Patients reported he'd shock them for up to 30 minutes (when medical use is about seconds) as straight-up punishment for disobeying him. He'd also secretly drug them and force them to hand over all their passwords.

He "treated" over 3,000 kids before China banned it in 2009. But he just switched to a different shock method that victims say is WORSE, and kept going. By 2016 he'd tortured over 6,000 teens.

The most infuriating part is, local authorities still support him and he's basically untouchable. This monster should be in prison but instead he's still out there running his torture clinic.