What kind of artworks do the guerrilla girls make?

They are photographers, designers, activists, and conceptual artists

Feminist posters :

Guerrilla Girls is an anonymous combination of feminist, female professionals dedicated to opposing sexism and prejudice in the art world. The association established in New York City in 1985 with the purpose of making gender and ethnic difference into focus in the numerous arts association. The group manipulates society jamming in the form of posters, brochures, billboards, and public presentations to present hatred and fraud. To remain anonymous, elements don gorilla costumes and use anonyms that regard to departed female artists.

The thing people think is that big heads mean big brain.

Well, in the music industry during the 80s  cyndi lauper took a risk in changing a certain type of music art into something creative with her hair dye and wild hairstyles that were bold, her style was entice and screeching that she actually did her get a lot of hate for it because at that time hair dye and crazy patterns wasn't the norm girl's just wanna have fun for example that changed the work of her genre and a lot of people were influenced by her ways. there was other people who took the dare but not a lot. that itself refers to change in art style, because modern times changed.