Mr. Z
From superman.nu: Supermanica
Mr. Z
A mysterious villain whose elaborate efforts to kill a small black and white stray dog seem bewilderingly inexplicable until Superman apprehends the villain and learns that he is really Oscar Lanchester, second in line to inherit his eccentric aunt's vast fortune, but only in the event of the death of her primary heir, her dog (S No.19/3, November/December 1942).