Mimic -Hoshokusha-

Mimic -Hoshokusha- is a two-chapter horror Hentai manga by Date.

An ordinary student council meeting is disrupted when a member who had left for home abruptly returns scared out of her mind, saying disturbing things. Leaving the council room to investigate, they find an oddly-acting teacher who regurgitates a strange goo that infests one of their own. Things go from bad to worse quickly...

Tropes used in Mimic -Hoshokusha- include:

• All Women Are Lustful: Or at least that's how the ones replaced by the creatures behave.
• Body Horror: While a creature is in the process of infesting and replacing a girl, the victim's skin bubbles up. Girls that have been replaced by the creatures have skin with a melted appearance.
• Bolivian Army Ending: The story ends with the now-replaced President, Maekawa and Okaniwa about to continue raping Aze and a lighter just barely out of reach. Whether he manages to escape or they proceed to consume him after having their way with him remains unknown.
• Cassandra Truth:One character suspects that another character has already been replaced by the creatures. The others don't believe him, and by the time he's proven right, it's too late.
• Deus Sex Machina: It's never explained why the girls replaced by the creatures are so sperm-hungry, as the creatures seem perfectly able to reproduce by infesting girls.
• Double Standard Rape (Female on Male): Played for horror; almost all the men who get raped are definitely not enjoying the act, and not just because the rapists are creatures masquerading as girls who will eat them once they can no longer maintain an erection.
• Glamor Failure: The girls that have been replaced by the creatures have skin with a melted appearance and dull eyes. It turns out they don't need to do so, and in fact are perfectly capable of hiding the fact that they're not the original until it's too late for the victim...
• Gory Discretion Shot: The last we see of Noguchi, some of the creatures are about to eat him. We never see him get eaten onscreen, though.
• If I Wanted You Dead...: Discussed; the characters argue that one of their own hasn't been replaced by the creatures without their knowing because she would have attacked already were she an impostor. As it turns out, they're wrong - the impostor is no unthinking being, but perfectly able to hold off on its desires until it could get one of them alone.
• It Can Think: The creature that replaced Okaniwa can suppress its lust long enough to fool Noguichi into thinking he's with the real Okaniwa rather than an impostor.
• Kill'Em All: By the end of the story, almost every named character has been either replaced or eaten by the creatures. The story cuts off before the fate of Aze, the last survivor, can be confirmed, but considering that three of the creatures are about to rape him again, his fate is most likely dire.

• Kill and Replace: The creatures act similar to The Thing, replacing females with themselves.
• Monster Misogyny: Played with. The creatures replace only females... because they rape and consume males.
• Negated Moment of Awesome: One character discovers that the creatures are repelled by fire. Before he can use this to escape or kill the creatures, however, his lighter is knocked out of his hands, the creatures assault him, and he gets killed.
• Orifice Invasion: The goo the creatures infest girls with isn't picky about which hole it enters from.
• Whole-Plot Reference: It's more or less The Thing as a school-set horror hentai.

• You Have Outlived Your Usefulness: If one of their victims can no longer maintain an erection, the creatures proceed to consume him.