Susan Walters moves from one CW show to another, cast on The Flash as the mother of Caitlin Snow (Danielle Panabaker). Her character, Dr. Carla Tannhauser, is likewise a biomedical engineer - so we get to see where Caitlin gets her natural talent for science.

Snow and her mother share a knack for science, but not much else, as their names suggest. In Tannhauser's first mention, when Earth-2 Killer Frost and Earth-1 Caitlin Snow met, they talked about their mother - and neither of them got along with her. With how different people and relationships were from Earth to Earth, it's saying something that they both had bad relationships.

According to EW's casting notice, "the two have long had a difficult relationship, with Caitlin finding her mother cold and withholding, and Carla regarding her daughter as rebellious and ungrateful."

The Flash comes back to The CW on Tuesday, October 4, 2016 at 8pm. The show occupies the Tuesday slot in the Monday-Thursday lineup of DC Comics superhero shows, with Supergirl, The Flash, Arrow, and Legends of Tomorrow each hitting in the 8pm timeslot each day. The four series will all crossover at some point this season, something Arrow star Stephen Amell teased Sunday with a simple image of boots of superheroes from all four series.

When The Flash returns, the world will be completely different, as the "Flashpoint" world is introduced after Barry Allen went back in time to save his mother. It's unclear how long that storyline will take to play out, and whether Walters will appear during that alternate world or on the "regular" one.

Walters has also appeared on The Vampire Diaries and Star-Crossed. She has one appearance, with the potential to recur.