I've seen the video of rolli robot. He's got some good mobiltiy and potential. What I imagine is one with the same mobility but with the ability to shoot pinkpong balls and battle other robots. The rolli robot would be able to roll to any area and then pop open and shoot the balls at a target of its choice. Little sensors could be stuck to the robots involved in the battle to determine target points, which could then be used to determine the rules and winner of the battle.
By Lord Duck
Other robots from Synthiam community

Ezang's Mr. Conehead Video For You To Watch In 2019
Mr. ConeHead video for you to watch 2019 - hope it is not to long

Ezang's Following, Tracking The Blue Line With ARC
Thanks for teaching us how to track - used ARC camera movement tracking, sorry for the squeaking, had the tail upside...

Justinratliff's Jd Backpack
I did a mock up of the JD backpack based on suggestions from @WBS00001 and @ptp from my C3PO JD head post. It has a male...