The Zygon Invasion (in-universe)

The Zygon Invasion was the seventh episode of the ninth series of Doctor Who. It followed The Woman Who Lived and was succeeded by The Zygon Inversion. It was first broadcast on BBC One at 8:15pm on 31 October 2015 and was forty-six minutes in length.

Its synopsis stated "When Osgood is captured by a rogue gang of Zygons, the Doctor, Clara and Unit must scatter across the world to set her free".

By 10 May 2020, the episode was available on BBC iPlayer along with the rest of series 9. Petronella Osgood watched it while in self-isolation. (WC: The Zygon Isolation)

Important note
This is a in-universe counterpart of the real world Doctor Who television story The Zygon Invasion that exists within the Doctor's universe. It was a visual meta-fictional cameo in The Zygon Isolation, where Petronella Osgood and her Zygon duplicate scroll through BBC iPlayer searching for something to watch.