The spell is a laser that tells the troops where you want them to attack .. maybe a town hall or dark elixer
it last for 3 seconds and only takes 25,000 to make when u upgrade it last 5 sec then 7 then 9 but it avoids your troops from spreading apart and when the time is done the units attack whatevers closest to them ..basicly it disables the preference of the units favorite building and goes after whatever you want it to go ..like lazer guided army ...