This week we not only learned that December's Arrowverse crossover event would be called Elseworlds (DC's catchall name for its 'alternate reality' stories) but would feature the first live-appearance of he legendary interdimensional being The Monitor.
The character will be portrayed by Sons Of Anarchy and The Last Ship star LaMonica Garrett.
You can read more about him and his character here on the DC Comics website.
What will appearance of The Monitor mean for our heroes? Could this result in a merging of Supergirl's world with that of The Flash and Arrow? How do Superman and Batwoman factor into all this?
While Elseworlds won't feature the Legends of Tomorrow (instead concentrating on The Flash, Arrow, and Supergirl), here's a trailer for the time travellers' magical new season: