I found this very unfortunate frog in the mouth of a Grass Snake (Natrix natrix)!
It was a sad sight to see but Mother Nature is brutal.
The snake held the frog in its mouth for at least 1,5 hours before it could swallow it.
Until the end I could see the frog breathing and the look in its eyes somehow showed a desperate hope that the snake would get tired and release it from its mouth.

Hortobágy-Halastó, Hortobágy National Park, Hungary, 2 May 2019