Doctor Who Flux: 14 Best Easter Eggs You Might've Missed

8. The Dark Times

Jumping to Once, Upon Time now, and this episode includes a quick, easy-to-miss shoutout to "the Dark Times", mentioned by Old Swarm during the Siege Of Atropos.

In the Doctor Who universe, the Dark Times was a period that pre-dated our known reality - essentially pre-history, or the time before time.

The Fugitive Doctor's role in the Siege Of Atropos helped bring about the end of the Dark Times by wrangling time itself under control, with the aid of the Mouri.

In the TV show, the Dark Times is a concept that hasn't been explored too much, although expanded media fans have a lot of material to chew on.