Challenge of the Super Friends (1978)

The Toyman devises a way to transmit people into books. The Legion uses Brainiac, Cheetah, and Giganta to lure Superman, Hawkman, and Wonder Woman respectively into the storybook tales of Gulliver, Jack and the Beanstalk, and Alice in Wonderland, respectively. In each case the villains lure the heroes into some danger and then disappear. The other Super Friends figure things out and manage to open the portal just before the books would be sealed for good and defeat the Legion.