First Appearance: Superman (vol. 1) #4 (Spring 1940): "Luthor's Undersea City"
Number of Appearances: 1
Enemy of: Superman
Worked for: Lex Luthor
Species: Tyrannosaurus Rex
Superman confronted Lex Luthor in a city Luthor had raised salvaged and raised from the sea. But Luthor had taken Lois Lane hostage, so he had Superman at his mercy. Luthor told Superman, "My innate generosity prompts me to give you a fighting chance for your life! Best the opponent I shall loose upon you, and you can go free with the girl!"Superman asked, "What's the catch?"
Luthor released the "opponent" and Superman saw what "the catch" was. The "opponent" was actually a monstrous dinosaur, apparently a Tyrannosaurus rex. The dinosaur was one of numerous prehistoric "monstrosities" Luthor had recreated in his biological labs in the salvaged undersea city.
The dinosaur rushed toward Superman in the city's coliseum. Superman said, "So all I've got to do is lick this baby, eh? Luthor, your generosity overwhelms me!"
The narrative caption describes, "Superman and dinosaur lock in a death-struggle. Seizing the beast by the tail, Superman whirls it up, then smashes it to the ground and out of the battle!"
With the dinosaur defeated, Superman stood by Lois Lane's side and looked up at Luthor, asking, "Well, satisfied now?"
Luthor apparently had no intention of honoring his pledge. He immediately ordered his henchmen to shoot Lois Lane and Superman. Of course, they escaped.
The conflict between Superman and the dinosaur took place in 3 panels on pages 11 and 12 of the story retroactively titled "Luthor's Undersea City" in Superman #4 (Spring 1940).