Used mostly in
anime and manga, the term growing mushrooms refers to when a character has become immensely
depressed or saddened. The character is often shown to literally grow mushrooms on their body, signifying that their soul is, for the time being, in a
dark and dank place. (Mostly occurs with more dramatic and over the top characters who can't stop crying every 2 seconds 😒)
Senpai: (crying because the
girl of his dreams thinks he's
dramatic and egocentric)
Girl: "Senpai, quit growing mushrooms around me; the smell is absolutely noxious!"