It doesn't mean anything, Juniper made a fake headline that stated (paraphrasing) "Julia Fox opened up about her relationship with Kanye: He didn't like it when I went 'goblin mode'" (the joke is that the reader is left hanging about what going goblin mode on Kanye even means), and it shoot up from there. Baffles me that it latched on, but I guess people intuit it means "slovenly" I suppose.