Several villains, including The Shade, Star Sapphire, Gorilla Grodd, Deadshot, Simon Stagg, Cheetah, Ultra-Humanite, Tsukuri, and Copperhead cameo briefly in John Dee's dream sequence (which is also the only point where Wonder Woman can be seen in the story). A figure in shadow in the background of the throng may or may not be Ra's al Ghul.
When Copperhead leaps on Hawkgirl, they resemble caduceus (international Health Symbol) with Hawkgirl's body posed straight and her wings extended, and Copperhead's tail twined around similar to the sign's snake.
In his dream, Dee refers to the ESP machine as the Materioptikon. In Mainstream Comics, the Materioptikon is the mystical stone that grants Doctor Destiny his powers in the world of dreams.