5. Brainiac
An android intelligence that roams the universe, seeking to gain information and sometimes destroy the original sources. He has a hobby of shrinking cities and storing them in bottles, including one from Supermans home planet called Kandor. Brainiac has been frequently suggested as a villain for Superman films but has never quite got there. (Although he appeared throughout season five of Smallville played by James Masters.) He could be made more like the Borg, intent on controlling the Earth, to be a greater threat. Superman could have heard that Brainiac is getting near and bring all the heroes together, in case he cant stop him by himself.