As you'd expect, this frog ends up as a bump in a snake's belly.
First off, this may be a fairly common European grass snake, but it has taken the uncommon road of trying to swallow its prey backwards. In a head-to-head contest, sometimes the frog gets away and other times the snake has its dinner and won't let go.
Such is the case here, as one slithering suspect has what it wants and doesn't dare lose its grip. It's just that the snake is in the awkward position of having to swallow the frog feet-first and it doesn't look easy.
In nature, it's eat or be eaten, and when an animal has to chase down and catch its prey every day or starve, you will get scenes like this.
Here's why we root for the hunters of the world.
Somewhere in a box of old VHS videos, I have some footage of this exact same exchange between a garter snake and a toad from way back in the early 1990s. It took forever for the garter snake to swallow the toad backwards, and the toad was making an awful racket.
There is really only one point to nature and its behavior in this way: survival. No one cares if a frog or a toad catches and eats every bug on the planet, but as the food chain rises, so does the level of intensity (and size) between the participants.