Colonel Colby
From superman.nu: Supermanica
Colonel Colby
Also known as "Big Con" Colby, Colonel Colby is a shady sideshow operator who is investigated by Jimmy Olsen. When Olsen discovers his deceptions, and gets into trouble for his efforts, he tries to summon Superman. Off on another mission, Superman's "secret weapon" Supergirl comes to his rescue instead. Olsen refuses to believe that there is a "super girl" (or her explanation of her origin) and thinks the Maid of Might is actually a circus strong woman from Colby's carnival show. It is finally left for Superman to apprehend Colby (SPJO No. 40/2, Oct 1959: "Jimmy Olsen, Supergirl's Pal").
