Deals 5 times X damage to each of up to X targets
So x spells have fallen out of vintage for a long, long time but they used to be the premier win condition. If you play old school, you would find that Fireball is one of the most common win conditions.
The reason I bring this up is because:
444RR : 20 damage to 4 targets
333RR : 15 damage to 3 targets
This is dealing lethal damage for significantly less mana than a Fireball. Is there anything else in the game that can one shot the opponent for just 11-14 mana?