They're generally just unattractive women who are incredibly bitter about it, they don't even enjoy the idea of sexuality or romance, but more are in it particularly to inflict pain upon men as well as other women who they perceive as better off than them. They're quite literally the mirror image of incels, and probably 50% as common, but they're definitely a real thing. They're just basically incels: insulting, belittling, angry all the time, have nothing nice to say to others. Usually racist, too, and have astronomical standards for men.