mischief virus

it's a virus, it obviously can't talk

it appears as a yellow mist, if you breathe it, you get infected

the infection infect any creature

An infection that turn something behavior, organic or artificial, into mischievous, playful, and cheerful.

the infection spread if you breathe, any infected can't infect survivor, any creature that can't talk will given an ability to talk, infected are conscious, but they accept the infection. the infection purpose is to bring happiness toward everyone, but most of them think this is dangerous