invisible spell

Ive been thinking of this for awhile now and i bet others as well what if they made a spell that allowed troops (doesn't matter dark or regular elixer). Would become momentarily invisible to all defenses as long as there in the spells circle perimeter it would be the same as when the archer queen lvl 5 cloaks herself invisible and heals but minus the healing. It would be a great addition to the awesome spells they have now plus it would only work on troops no heroes. .. what do you guys think it would be like a freeze spell but with the benefit of your troops causing damage , it wouldnt be a long invisible cloak it would be like 4.5 seconds and become a little more as you lvl up the spell