Well seeing that I don’t have much faith in 343 being any more original than Bungie was with Halo Reach, I thought it best to start throwing new gametypes out there for this next big thing so we don’t have to further Reach into the Unreal Tournament franchise for our headhunters/greeds, firefights/invasions, and invasions/assaults. 
So there we have Grunt Hunt. The idea is simple, spawn a single grunt (or any AI depending on what the player/developer has set) into the middle of a team based multiplayer game. He runs, cries, and dies in a very violent manner to the pleasure of all concerned as they scamble for the mobile piniata in what doubtlessly will all make us sinful -Yoinks!- in darkest pits of gaming hell. Players thus can only score points by killing the target, but are free to open up the other side(s) in order to run “tactical interferance.”
Alternatively the Grunt can take the role as “bonus points” for a standard (multi) team slayer game, but the principle is the same and VERY simple to implement once we catch up to the shooters of yore as far as bots and multiplayer is concerned. Pathing shouldn’t be too much of a problem, either, because the crux of the fun doesn’t lie with the target actively participating in combat (apart from the screaming.)