A group of previously unseen trophies has appeared on PS3Trophies which appears to show that a new DLC pack for Batman: Arkham City is in the works and will be centred around Harley Quinn.

Not only does the link show new trophies but also suggests that the DLC will be a mini-campaign rather than just another set of challenge rooms. The leak also suggests that players will be able to take control of the Dark Knights sidekick Robin.

The new trophies are as follows:

Lost Property
No crime fighter should be without this
Breaking and Entering
Find a way into the secret base
How’s It Hanging?
Clean up the Dry Docks
The Last Laugh
The joke’s on who?
Frequent Flyer
Zip Kick 3 different thugs
Battering Ram
Shield Bash 5 different thugs
Snap To It 
Snap Flash an unarmed thug, an armed thug, an environmental object and a Titan
Bomb Squad 
Defuse all bombs in 3 minutes or less
A Few New Tricks
Use 5 different Quickfire gadgets in one fight as Robin in Harley Quinn’s Revenge
Party’s Over
Destroy all Harley Balloons

Obviously Rocksteady and Warner Bros haven’t confirmed anything but we will keep you informed of any official news.