Omnicidal Maniacs want to destroy the world, and just like them, villains who want To Create a Playground For Evil want to destroy the world too... but in another way. Rather than blow it up or kill everyone on it, they much more content to simply turn it into the most horrible and messed up place possible - their own personal playground, in other words. Villains who intend on this goal are likely Complete Monsters, and doing it For the Evulz.