This Golden Age mad scientist appeared in Fox's WEIRD COMICS #1-6 (April 1940-July 1941) and THE FLAME #4 (February-March 1941). Dr. Mortal was created, scripted and drawn by self-taught ex-newspaper cartoonist Bert Whitman. His comic strip, DEBBIE DEAN (Mort Drucker was one of his assistants) infamously fell under fire when he used the word "dope" in one of his episodes, which lead to cancellations from many papers, forcing him to cancel the strip.
In each of his stories, Dr. Mortal was attempting all sorts of nefarious experiments to create some kind of monster, usually involving his unwilling niece, Marlene. In this untitled story from WEIRD COMICS #2 (May 1940), he uses human cadavers and lion intestines to create a group of murderous lion-men. Yikes!