FYI there has been Ability world/ladders for the past several weekends. They are available for 6hrs blocks at these times (pacific standard) 1am-7am, 7am-1pm, 1pm-7pm and 7pm-1am. Sometimes they will switch to Shaders so make sure you view the bonus reward before you start it and pay the credits.
Go to the Multiverse and look one of the smaller planets in the middle. There will only be one mission that is a boss. If you hit "2" when looking at the world you will see the bonus rewards, one if which is a random ability (or shader). It will cost you $150,000 credits to play it.