original idea a bit to OP, but with tweeks it could work well.
Maybe a basic trap that does not take any upgrades (like spring trap) which can be placed on a building and makes it immune to 1 spell?
So, you could place this trap on your DE storage and it would stop 1 lightning hit? Then would need to be reset. Since sooooo many folks complain about lightning zaps on DE this might be a nice option.





