A new boom? The Mist!

I have a Idea for a new boom. A boom that only make a mist so that the attacking troops cant see the buildings in the mist, and will move on to a building that is outside of the mist. This can help the defense by giving them more time to shot on attacking troops wen they are moving to another building.

It could be a Dark Exile boom. And it could be a 3 level upgrade and with a trigger radius of 2 tiles.

Level 1, the mist "damage area" 2 tiles and last for 3 sec(time building would be hidden from the attacking troops).

Level 2, the mist "damage area" would be 3 tiles and last for 5 sec.

Level 3, the mist "damage area" would be 5 tiles and last for 8 sec.