In a just-released clip from DC's Legends of Tomorrow, Smallville fans are likely to recognize a name that gets dropped.
That would be Curtis Knox, the name of a doctor...and an alias for Vandal Savage.
Why's that relevant? Well, in Smallville, Dean Cain played Dr. Curtis Knox...who, according to writers, was originally intended to be Vandal Savage before DC asked them to change the name.
(This wasn't a one-off thing; Batman and Booster Gold faced off against somebody who was pretty clearly Vandal Savage, but with a different name, in an episode of Batman: The Brave and the Bold.)
In Smallville, Knox targeted metahumans with high concentrations of kryptonite in their system, which he would then transplant into his wife's body. He killed Sasha Woodman and targeted Chloe Sullivan, before coming across Clark and Martian Manhunter. The prevailing theory is that J'Onn exiled Knox to the Phantom Zone; he admitted that he couldn't kill him since Knox was immortal.
Both Knox's origins and powers matched up with Savage's, and so using Knox's name to give Savage an identity to hide behind on Legends is pretty ingenious.
Funny enough, Cain will share the screen with Martian Manhunter again...in Monday's episode of Supergirl, which flashes back to when his character (Jeremiah Danvers) first met J'Onn J'Onzz.
DC's Legends of Tomorrow airs Thursdays at 8 p.m. ET/PT on The CW.