Playing dead is a common defensive move among animals. But the hognose snake is insistent about it. At the end of the video, they try to flip the snake the right way around, and it almost instantly ripples its body so that it's on its back. As if it's saying, "I'm DEAD, okay? Leave me alone."
The other sign of commitment? The open mouth with tongue hanging out. Looking into the hognose snake reveals that the fake out is the only move in the hognose's tool bag. First, they'll puff out the skin around its head and neck to pretend to be the much more dangerous cobra. Even going so far feint lunging bites.
And if that doesn't work, playing possum is next. Flipping over on their back, tongue out, even emitting a smell like a corpse. Nice try, hognose. But, like so many actors, over-committing to the role rumbled you.