Plunder Mars (6)
I believe the answer is:
spoils
I believe this is a double definition.
'plunder' is the first definition.
(I've seen this before)
'mars' is the second definition.
('spoil' can be a synonym of 'mar')
(Other definitions for spoils that I've seen before include "Plunder, benefits to victor" , "Plunder, takings from war" , "Damages" , "Cossets, fails to instil discipline into" , "Booty" .)