Succubus Appli: Gakuen Sai*

When a mysterious app appears on his phone, a high school boy discovers he can hypnotize anyone simply by snapping their photo — and naturally, the first thing he does is test it on his classmates. That's the premise of Succubus Appli: Gakuen Sai, a 4-episode OVA from 2021 that leans hard into its hentai roots while dressing everything up in a familiar high school setting. The app, apparently gifted by a succubus, gives protagonist Oda Yuuma a peculiar kind of power over the people around him, including his assertive classmate Fujimiya and the notoriously strict disciplinary committee head Akizuki Sakurano. The supernatural hook here — a demonic smartphone app — gives the series a slightly different flavor compared to more straightforward entries in the genre. It's not reinventing anything, but the blend of everyday school life with a low-key supernatural twist keeps things from feeling completely generic. The character designs are distinct, and the short episode count means it moves quickly without much padding. If you've watched something like Welcome to Succubus High or Succubus Academy and want more of that school-setting energy with a tech-flavored supernatural twist, this fits that same niche. Same goes if A Swelling Succubus was your kind of thing. It knows exactly what it is and doesn't pretend otherwise — four episodes, a fun absurd premise, and a very specific audience in mind.