Influencers are people on social media that distinguish themselves by the high number of followers and the ability to influence other users. While influencers are a long-standing phenomenon in social media, virtual influencers have made their appearance on such platforms only recently: they are CGI characters that act like and resemble humans, even if they do not physically exist in the real world. This recent phenomenon has sparked interest in society, and several questions arise regarding their evolution, opinions, ethics, purpose in marketing, and future perspective. In this article, we conduct an exhaustive review of the virtual influencer phenomenon. Through an extensive study of the literature, press articles, social platforms data, blogs, and interviews, we give a comprehensive reflection on virtual influencers. Starting from their evolution, we analyze their opportunities and threats. We provide detailed information about the most popular ones and their marketing collaborations, with a comparative analysis of virtual and real (human) influencers. Moreover, we conducted an online survey to grasp people's perspectives. From the 360 participants' answers, we draw conclusions about virtual influencers' ethics, importance, overall feelings, and future. Results show controversial opinions on this recent phenomenon. @en