Understood! Here's a brief synopsis of the story I have in mind:

The story takes place in a world where swans have been infected with a mysterious, malevolent force. The infected swans are slowly losing their humanity, transforming into monstrous creatures with black eyes, elongated necks, and sharp teeth. As the infected swans begin to spread their corruption, a group of survivors must work together to escape the nightmare and find a way to stop the infection before it's too late. You and ugly duckling Was been safe and other try to too