In Jeph Loeb and Ed McGuinness's epic Superman crossover 'Emperor Joker', we find the world reinvented to the Clown Prince of Crime's specifications. Having stolen 99% of annoying Superman villain Mr. Mxyzptlk's powers (think 'Star Trek's Q, except even worse), the Joker becomes an omnipotent being; the whole world his playset. Superman, realising that something is amiss, attempts to right the balance.
Chief among his achievements as Emperor Joker was the daily torture and murder of nemesis Batman, resurrecting him every day so as to repeat the process. Such sport would eventually prove to be his downfall, with Superman recognising Joker's obsession with Batman as his only weakness, exploiting it accordingly.
Poor Batman was left so traumatised by the experience that he had to have his memory wiped in order for him to be able to function again. At least Joker met his downfall with a full belly - having eaten the entire population of China beforehand, just for fun.
Horror and Batman fanatic, Haribo fiend and Nicolas Cage scholar. I write a lot, drink even more and can usually be found listening to the work of Queen while styling my hair in an increasingly ridiculous quiff.