Fallen Hana (also known as Evil Hana) is the un-official name of the main antagonist of the 2014 Short anime musical Animation, Nihon Animator Mihonichi: Episode 3, ME!ME!ME! along with the Memes.
According to explanations from internet sources such as Youtube Explained, Fallen Hana, as well as the illusory world she lives in, represents Shuu's addiction to the otaku lifestyle and the strain it placed on his relationship with Hana; his obsession with video games and anime left him a shut in, to the point where he ignored his girlfriend's attempts to get his attention and reintegrate him into a healthier lifestyle. Fallen Hana as well as her minions end up consuming him just as his obsession does. Like in the video, he is unable to save his relationship with Hana and his realization comes too late.
Her behaviour and design, as well as that of the CPUs, could also be a reflection of how women are shown and treated in video games, anime and manga: often not very respectfully and objectified as things to excite male viewers, with bared skin and an overt desire for the male protagonist being their more defining characteristics. The video takes a jab at this view by showing the women of the video being dangerous and predatory to Shuu, and showing that his relationship with an actual girl was destroyed by his fantasies of women that ended in his symbolic destruction. Fallen Hana's appearance shows the fantasy world colliding with the real world in ways that it shouldn't, and means Shuu losing his grip on reality.