Superman: The Mechanical Monsters

The Mechanical Monsters is the second of the Fleischer Studios Superman cartoons, released by Paramount in November 1941. A mad inventor sends an army of flying robots to loot Metropolis — banks, jewel houses, anything they can carry — and captures Lois Lane when she stows away inside one of the machines. Superman battles the mechanical army and flies to the inventor's lair to save her from a vat of molten metal. The robot designs influenced decades of animation, from Sky Captain and the World of Tomorrow to a famous homage in The Iron Giant. The film entered the public domain through non-renewal.