Smallville: 10 Best Characters Only In One Episode
3. Curtis Knox
Much like The CW's Supergirl does today, one of the fun elements of Smallville was getting to see certain familiar Super-associated faces turning up in the series. Christopher Reeve, Margot Kidder, and Teri Hatcher all put in memorable Smallville appearances, but no Super alum impressed as much as former Man of Steel, Dean Cain.
As Dr. Curtis Knox, Cain got the chance to ham it up in the 'Alien' episode as an evil immortal being intent on harvesting the organs of anyone who had traces of kryptonite in their system.
Far removed from the ever-smiling good guy audiences usually associate Dean Cain with, Knox was a true piece of work. And across all ten of Smallville's seasons, few 'villains of the week' posed as much of a threat to Clark and his buddies as this demented doctor.
To reiterate his invincibility, we even got to see Lex Luthor shoot Knox six times - only for the Doc to merely shake that off with ease. Even when Clark electrocuted Knox, that still wasn't enough to keep Curtis down for the count. Truth be told, the only reason why Curtis Knox stopped his rampage was due to the death of his wife during Knox's episode-closing fight with Clark.