I believe that 2v2 modes for Rumble are being worked on, and in that case, adding shiftstones based around the idea could be cool. Most basic idea is a simple “Friend Stone” which could cause you to not deal any damage or kb to teammates. I also think it’s important that if you equip the stone, you should still take damage from teammates. If you don’t have enough control to not hit your friend, then you should be paying a price via one shiftstone slot. Having a bad teammate and being forced to switch to Friend Stone would be really frustrating. Another idea I had is a combo shiftstone, where hitting an enemy with either a structure given to you by a teammate or after your teammate hits an enemy would give some sort of boost. So, if my teammate tosses a cube at me, I flick catch it, and that cube hits an enemy (all of this would probably be within 8 seconds or so), then I’d get the buff, and if my teammate also had the combo stone, he’d get it too. As for what the buff could be, I don’t think a damage up would be good, as that might be too dominant in high coordination environments. Maybe getting a one time use air movement like Flow, Adamant damage reduction, Vigor healing or something completely new! Of these, I like the one time use air dash, as it allows you to stay on offense, quickly retreat, or save the air dash for when you get knocked out. This would be especially interesting if it could stack with Flow, giving a third air option. Of course, a simpler effect would be fine too. But mainly, a stone that encourages coordination would be really cool to see.