Neko wa Kira Jošikage ga suki (S03E30)

Kawajiri hears from Shinobu that there is a British Blue cat in the basement with a hole in its neck. Kawajiri wonders if it was shot with the arrow, and goes down to check, however all he finds is a dead cat. Shinobu, frightened by the cat, started to swing around a broom frantically and knocks over a glass bottle. Some of the glass fragments pieced the cat, killing it. Kawajiri buries the cat in their yard, but the next day, a strange plant grew in the place where the cat was buried... (Crunchyroll)