Okay so I've been thinking about a new spell called the bat spell. so when you drop it a red ring appears. any defense is distracted from your troops. they will attack your troops again after 10 seconds. time increases by 2 or 1 seconds each time you upgrade it.
Seems very overpowered, to make it seem understandable you would have to make it probably around five seconds starting off, with a tile radius of 2, and at that point it becomes a freeze spell, doesn't make sense to remake a spell.