Available on Prime Video, Crunchyroll
S1, E5: Yuuki Reiko, member of the Occult Club, barges into the Sket-dan's room holding a picture of one of Kaimei Academy's seven mysteries, the "Ghost of the Incinerator". The Sket-dan are on the case (mainly Switch), trying to find out the truth behind the picture, and getting Shimada Takako from the Newspaper Club mixed up in it, too...
Anime · May 5, 2011 · 24 min