Arrow baddie William Tockman aka "The Clock King" (played by Robert Knepper) will make an appearance in episode 7 of The Flash.
But there's a catch..
According to EP Andrew Kriesberg, Knepper's Clock King won't be working alone to bring down Grant Gustin's metahuman.
We wanted to give Barry a real challenge… TWO bad guys! Barry will be fighting both a new enemy and one of our scariest and most successful Arrow villains in The Clock King.
The EP did not spill any details on the second comic villain, so stay tuned!