They can single handedly wipe an entire loon/lava raid.
Pretty overpowered and I am not even having problems with them. I'm watching mine completely destroy attackers in war. It's a great defense, but it's beyond ridiculous against air. At least when on ground, the troops can fight them off. Loons and lavas just sit there while they are completely wiped out.
Give them a much shorter time cap or only allowed them to cause a certain amount of damage.

