The grass snake
The grass snake (Natrix natrix) is a common snake that lives near water habitats in Europe. It is a predator, but also prey. In spring, meatballs of these snakes could be found entangled.
This is a non-venomous snake, so, it’s no threat to people. In the case of the danger, it will pretend to be dead or if caught, it will release a smell from its glands.