A while back I suggested tar trap. This never came to be so i was thinking that a tar spell could be used for attacking and defense.
Attack: the spell slows and slightly damages defending troops and defensive buildings. This would be most beneficial against xbow and inferno tower.
Defense: since you are not involved in defense when attacked you could set predetermined locations where the spell should be used depending on amount of damage taken in a certain location. This could help prevent spell being used against I attacking troop.
