Xlym
From superman.nu: Supermanica
Xlym
A distant planet inhabited by advanced aliens who are curious as to whether Superman or Batman is the most skilled crusader against crime. To even the odds, the Xlymians give Batman super-powers and subject both heroes to memory loss and a temporary animosity effect using a series of scientific ray technologies. Back on Earth, the world's mightiest team engages in a fierce rivalry to outdo one another, until the temporary changes eventually fade away (WF No. 95, Jul/Aug 1958: "The Battle of the Super-Heroes!").
