holy CRAP, a bird box-like thing would be... absolutely insane, LMAO. i am leaning towards that or the zombies/illness idea? something like the last of us, maybe?
i'm ngl, i do like writing exploration/action/the aftermath of said scenes so i'd prefer something living (or victims that are living? undead in zombie-style also works lol) that can be interacted with or avoided, but if that's not up your alley that's fine as well. :D