A Certain Scientific Railgun A Certain Scientific Railgun T Episode 24 Diffusion ( Air Date 2020-09-18 ) Genre Animation, Action & Adventure, Comedy, Sci-Fi & Fantasy category. Overview "To counter the Doppelganger's giant monster form, Mikoto creates a giant magnetically-induced monster of her own. As the two do battle, it becomes evident that the Doppelganger has an ultimate objective other than combat in mind.".