Rain

Rain spells are surprisingly low aggro nukes that hit up to two targets at once, 3 times in a row. Each wave of the rain is subject to its own resist check. The Rain can and will hit the caster if he is too close. Rains tend to have a shorter cast range then regular nukes.

Rain spells have 1/3 the crit rate of normal direct damage spells.

Rain spells are the Magicians bread and butter, but other classes get them as well. If you have more than 1 mob, rains are pretty much the most bang for your buck mana wise.