Last night we saw the first Flash/Supergirl crossover teaser, and here’s another one. Just like the first, it’s short and non-spoilery.
https://youtu.be/kUHoHBfiJUA
And Flashfans.org has posted some official stills from the episode here. They have spoilers and show who the villains are, just to give people some advance warning.
The episode will air on March 28th, so mark your calendar!