Emily Kinney, the young actress who played Beth on The Walking Dead, is coming to The Flash as the villain known as the Bug-Eyed Bandit. Interestingly enough, the Bug-Eyed Bandit is a villain of the A.T.O.M., so there is a good chance Ray Palmer could team up with Barry to take her down.
The Bug-Eyed Bandit in the comics is usually male, so it is interesting to see the writers choosing to make the character female in the TV universe. Some fans might throw a fit, but you know what? It doesn't matter because the Bug-Eyed Bandit is not a famous villain by any means, and thus is capable of being changed around as much as possible.
As TV Line reported, Kinney will figure in Episode 18 of The Flash titled "All-Star Team Up." This is the episode where Ray Palmer and Felicity will make an appearance in Central City in the hope that S.T.A.R. Labs will help with the creation of the A.T.O.M. suit that should allow Palmer to shrink his mass to ant-like size.