The Man Who Knew Superboy's Secret - S1.E4

A man arrives claiming to know that Superboy is really Clark Kent. The man claims to be from Krypton. He offers Superboy an antidote to Kryptonite. The man is really an alien from another planet who wants to trick Superboy into losing his powers. Superboy does not fall for the deception because he is suspicious of the man due to a scar on his body.