What workout video do you find surprisingly challenging?

For me it's this one: https://www.fitnessblender.com/videos/bodyweight-cardio-training-lower-body-strength-37-minute-butt-and-thigh-workout

Old workout video, but man it always leaves me sweating and puffing. It burns a lot of calories (357 low end! with no added weights needed!) in only 39 minutes (no warm up but cool down included). I really enjoy going back and doing videos I haven't done since I started FB like 6 years ago. I often find their older videos are a little more challenging- could just be because of the different format.

So, what's one of your old favorite videos that's surprisingly challenging?

Edited