Under a short duration, I'd say starting at 1.5 seconds upgradeable, a selected group of units in a area of 50-40 squares reflect back all damage done to them however does not "remove" the damage they take. It would not be a ring spell such as healing, more so that the units can move out of selected area and the effect would still be on them. Reasoning behind this is that certain layouts are simply overpowered currently, like "isle" layouts in ways for example, how ought you to handle 4 mortars, all archer towers, wizard towers, cannons, 3 maxxed x-bows, CC troops triggering, and 1 hero assuming you killed one coming in at the same time as freeze wears off inferno towers? You don't, every unit on that isle will die, and whatever you have left is what is to get the 2 star as 3 is not a possibility. This would force people to change layout types to more strategic ones instead of "heatzone" mapped ones. TH9 spell naturally.